Sách Giáo Khoa Hóa Học 10 Nâng Cao

" Sách Giáo Khoa Hóa Học 10 Nâng Cao 🔙 Quay lại trang tải sách pdf ebook Sách Giáo Khoa Hóa Học 10 Nâng Cao Ebooks Nhóm Zalo BQ GIAO DUC VA OAO TA I NANG CAO NHA XUAT BAN GIAO DIIC VlEl NAM BO GIAO DUC VA OAO TAO LE XUAN TRQN G (Tong Chu bien kiem Chu bien) TU NGOC ANH - LE MAU QUYEN - PHAN QUANG THAI HOA HOC NANG CAO (Tai ban Ian thu nam) N H A XUAT BAN GlAO DUC VIET NAM Chiu trach nhiem xuat ban : Chu tich HDQT kiem Tong Giam doc NGO TRAN Al Pho Tong Giam doc l,?iK,^gCa,2|^h . b) H^He,lc,^l0,?^P,iFe. 5. Ytri (Y) dung lam vat lieu sieu din co sd khdi la 89. DUa vao bang tuan hoan, hay xac djnh sd proton, so natron va sd electron cua nguyen til' nguyen td Y. 11 DONG VI. NGUYEN TU KH6 I VA NGUYEN TIT KH6 | TRUNG BJNH • The nao la dong vj, nguyen tur khoi, nguyen tijr khoi trung binh ? • Cach xac djnh nguyen tur khoi trung binh. • DONG VI Cac nguyen tir ciia cung mdt nguyen td hoa hgc cd the cd sd khdi khac nhau. So dl nhu vcly vi hat nhan ciia cac nguyen tir dd cd cung sd proton nhung cd the khac sd notron. Cdc ddng vi cua cung mgt nguyen td hod hgc la nhitng nguyen tic co cung so proton nhung khdc nhau ve sd natron, do do sd khdi A cua chung khdc nhau. 0 cac ddng vi dugc xep vao cung mdt vi trf (d nguyen td) trong bang tuan hoan. Thf du nguyen td hidro cd ba ddng vi : a)Proti(]H) © Hat nhan gom 1 proton (tri/dng hop duy nhat khong co notron),chiem 99,984% s6 nguyen tii hidro tu nhien Hat electron b)Dateri(^H) Hat nhan gom 1 proton va 1 natron, chiem 0,016% so nguyen tir hidro tu nhien O Hat proton c)Triti(^H) Hat nhan gom 1 proton va 2 notron (trudng hap duy nhat c6 s5 natron bing 2 Ian so proton). D6ng vi nay chi chiem khoang 10^^% so nguyen tu hidro tu nhien • Hat natron Hinh 1.4. Sa do cau tao nguyen tCl cac dong vi cCia nguyen to hidro Phan ldn cac nguyen td hoa hgc la hdn hgp ciia nhieu ddng vi. Ngoai khoang 340 ddng vi tdn tai trong tu nhien, ngudi ta da tdng hgp dugc hon 2400 ddng vi nhan tao. Cac ddng vi cua cung mdt nguyen td hoa hgc cd sd notron trong hat nhan khac nhau, nen cd mdt sd tfnh chat vat If khac nhau. Thi du : C) trang thai don chat, ddng vi 37 Q^ cd ti khdi ldn hon, nhiet do ndng chay va nhiet do sdi cao hon ddng vi 17CI. 12 Ngudi ta phan biet cac ddng vi b6n va khdng ben. Hau het cac ddng vi cd sd hieu nguyen tir ldn hon 82 (Z > 82) la khdng ben, chirng cdn dugc ggi la cac ddng vi phdng xa. Nhieu ddng vi, dac biet la cac ddng vi phdng xa, dugc sir dung nhieu trong ddi sdng, y hgc, nghien cUu su phat trien cua cay trdng,... II - NGUYEN TU KHOI VA NGUYEN TU KHOI TRUNG BINH 1. Nguyen tir khoi Nguyen tir khdi la khdi lugng tuong ddi cua nguyen tir. Nguyen tic khdi cua mgt nguyen tic cho bie't khdi lugng cua nguyen tu do ndng gdp bao nhieu ldn dan vi khdi lugng nguyen tu. Khdi lugng ciia mgt nguyen tir bang tdng khdi lugng cua proton, notron va electron trong nguyen tu dd. Proton va natron deu cd khdi lugng xap xi 1 u. Electron cd khdi lugng nhd hon rai nhieu (0,00055 u), nen cd the coi nguyen tir khdi xap xi sd khdi ciia hat nhan. 2. Nguyen tir khoi trung binh Hau hei cac nguyen td hoa hgc la hdn hgp cua nhieu ddng vi vdi ti le phan tram sd nguyen tir xac dinh, nen nguyen tir khdi cua cac nguyen td cd nhieu ddng vi la nguyen tir khdi trung binh ciia hdn hgp cac ddng vi cd tfnh den ti le phan tram sd nguyen tir cua mdi ddng vi. Gia sir nguyen td cd hai ddng vi A va B. Ggi A la nguyen tir khdi trung binh, A la nguyen tir khdi cua ddng vi A, a la ti le phan tram sd nguyen tir cua ddng vi A ; B la nguyen tir khdi cda ddng vi B, b la ti le phan tram sd nguyen tir cua ddng vi B. Ta cd : - aA + bB A = 100 Trong nhung tfnh toan khdng can do chfnh xac cao, ngudi ta coi nguyen tir khdi bang sd khdi. Thi du : Nguyen td clo cd 2 ddng vi ben ^^Cl chie'm 75,77 % va ^yjC\ chiem 24,23%. Nguyen tir khdi trung binh ciia clo la : — 75 77 24 23 13 BAI TAP 1. Nguyen td cacbon co hai dong vj ben : ''§C chiem 98,89% va ''^C chiem 1,11%. Nguyen tCr khdi trung binh cua nguyen td cacbon la A. 12,500 C. 12,022 B. 12,011 D. 12,055 Chgn dap an dung. 2. Cho biet sd proton, sd natron va sd electron cua cac dong vj sau day : „v 28qi 29c: 30qi a) 1401, 1401, -1401 • y.s 54p - 56p p 57 p 58 p D) 26'^®' 26'^®' 26'^®' 26^® - 3. Nguyen tCr khdi trung binh cua bac bang 107,02 Ian nguyen tu" khdi ciia hidro. Nguyen tCr khdi cua hidro bang 1,008. Tfnh nguyen tCr khdi trung binh cua bac. 4 Cho hai dong vj hidro va hai dong vj cija clo v6i ti le phan tram sd nguyen tu" chie'm trong tu nhien nhu sau: ]H(99,984%),^H(0,016%), ^^Cl(75,77 %), ^^1 (24,23%). a) Tfnh nguyen tu" khdi trung binh cua moi nguyen td. b) C6 the CO bao nhieu loai phan tCr HCI khac nhau tao nen tU hai ddng vi cua hai nguyen td do ? c) Tfnh phan tu" khdi cua m6i loai phan tu" noi tren. 5 Nguyen tCf khdi trung binh cua dong bang 63,546. Trong tu nhien, dong c6 hai dong vj 29CU va ||Cu . Tfnh ti le phan tram sd nguyen tCrcua dong vi ||Cu ton tai trong tu nhien. i Cho hai dong vj ^JH (kf hieu la H) va ^H (kf hieu la D). a) Viet cac cong thdc phan tu" hidro c6 the c6. b) Tfnh phan tCr khdi cua m6i loai phan tCr. c) Mgt li't khf hidro giau dateri ( ^H ) d dieu kien tieu chuan nang 0,10 g. Tfnh thanh phan phan tram khdi lugng tdng dong vj cua hidro. ^itliiu. SU PHONG XA 1. Sir phan ra hat nhan - phong xa va phan hach Tfnh phdng xa la tfnh chat ciia mot sd hat nhan nguyen tu khdng b^n cd the tir bien ddi va phat ra cac buc xa hat nhan (thudng dugc goi la cac tia phdng xa). Cac nguyen tu cd tfnh phdng xa goi la cac ddng vj phdng xa, cdn cac nguyen tii khdng phdng xa goi la cac dong vi ben. Cac nguyen td chi gdm cac ddng vi phdng xa (khdng cd ddng vj ben) ggi la nguyen to phong xa. 14 Tia phdng xa cd the la chum cac hat mang dien duang nhu hat a (phdng xa a), hat proton ; mang dien am nhu chum electron (phdng xa p) ; khdng mang dien nhu hat ncrtron hoac tia y (cd ban cha't gid'ng nhu anh sang nhung nang lugng Idn han nhieu). Su tu bien ddi nhu vay ciia hat nhan nguyen tu, thudng ggi la su phan ra phdng xa hay phan ra hat nhan. Tu phan hach, la qua trinh hat nhan ciia cac nguyen tu phdng xa cd sd khdi Idn nhu 235U tu va ra thanh cac manh hat nhan kem theo su thoat ra natron va mdt sd hat ca ban khac, cung la mdt dang cua su phan ra hat nhan. Trong tu phan hach va phan ra hat nhan deu cd su hut khdi lugng, tuc la tdng khdi lugng ciia cac hat tao thanh nhd han khdi lugng ciia hat nhan ban dau. Khdi lugng bj hao hut nay chuyen hoa thanh nang lugng khdng Id dugc tfnh theo phuang trinh ndi tieng ciia Anh-xtanh (A.Einstein) : AE = Am.c2. Trong dd, AE la nang lugng thoat ra khi phan ra hat nhan (nang lugng nay nam trong ddng nang cua cac hat thoat ra khi phan ra hat nhan va nang lugng ciia buc xa y); Am la do hut khdi ; c = 2,988.10^ m/s la van tdc anh sang trong chan khdng. 2. Sir phong xa tir nhien Nam 1896, nha vat li ngudi Phap, Bec-ca-ren (A.Becquerel) va sau dd la dng ba Pi-e Quy-ri va Ma-ri Quy-ri (Pierre Curie va Marie Curie) phat hien ra rang cac hgp chat ciia urani cd kha nang tu phat ra nhung tia khdng nhin thay dugc, cd the xuyen qua nhung vat ma tia sang thudng khdng di qua dugc, ggi Man huynh quang Ong chan khong Ban tu dien Chat phong xa la cac tia phdng xa. Dudi tac dung ciia dien trudng tia phdng xa bj tach lam ba tia : Hinh 1.5. Su phong xa tu nhien - Tia a (anpha) lech ve phfa cue am ciia dien trudng, gdm cac hat a mang hai dien tich duang, cd khdi lugng bang khdi lugng ciia nguyen tu heli. - Tia P (beta) lech ve phia cue duang ciia dien trudng, gdm cac hat electron. - Tia Y (gamma) khdng lech ve cue nao eua dien trudng, ed ban chat gidng nhu tia sang (hinh 1.5). Nhung nghien cuu ve ban cha't eiia hien tugng phdng xa chung td rang hat nhan eua eac nguyen tu phdng xa khdng ben, ti/phan buy va phdng ra cae hat vat chat khac nhau nhu hat a, P, kem theo bue xa dien tu nhu tia y. Ddng thdi vdi hien tugng phdng xa tu nhien, ngudi ta cung phat hien mdt sd loai nguyen tu eiia mdt sd nguyen td nhan tao cung ed kha nang phdng xa. 15 3. LTng dung cua dong vj phong xa Mac du mai tdi nam 1896 hien tugng phdng xa mdi dugc phat hien bdi nha bac hoe Phap Bec-ea-ren, nhung eae ddng vj phdng xa da nhanh chdng ddng vai tro dang ke trong Ijch su phat trien ciia the ki XX va the ki chiing ta dang sdng. iJ'ng dung ddng vj phdng xa trong cac iTnh vuc khae nhau eiia kT thuat va ddi sdng ehij yeu dua tren hai yeu td : (1) Tuang tac manh ciia tia phdng xa vdi moi trudng vat ehat ma nd di qua ; (2) Do su phat tia phdng xa, eae ddng vj phdng xa d& duge phat hien bang eae may do phdng xa, nen ed the ddng vai trd cua cac nguyen tu danh dau. Sau day la mdt vai thf du v^ ung dung ddng vi phdng xa. a) Trong nghien cxru sinh hoc va nong nghiep Trong nhung thanh tuu rue ra gan day eua nghien cuu di truyen hgc, giai ma gen, tim hieu su van chuyen cac axit amin trong ea the sinh vat,... vai trd eiia cac nguyen tu danh dau la rat quan trgng. Cac tia phdng xa cd nang lugng Idn, gay ra eae ddt bien gen tao thanh cae gidng mdi vdi nhieu tfnh ehat uu viet. Day la ea sd eiia each mang xanh tren the gidi. Tia y eiia ddng vj ^oCo la tac nhan tiet tning, chdng nam mdc huu hieu trong bao quan luang thuc, thuc pham va eac loai hat gidng. bJ Trong y hoc Trong y hoc, cac ddng vi phdng xa dugc dung rdng rai cho hoat ddng nghien ciiu, chan doan va dieu tri. Cac hgp chat danh dau hoa phdng xa cung cap cac thong tin giai phSu hoc ve noi tang con ngudi, ve hoat ddng ciia cac ca quan rieng biet, phuc vu cho chan doan benh. Tia phdng xa dugc sd dung trong cac phuang phap chup cat lap. Tu lau ngudi ta da sd dung ddng vi ^^i j trong chan doan va dieu trj benh tuye'n giap. Tia y co the hdi tu tao thanh chCim tia cd nang lugng Idn, dugc su dung nhu mot luai dao sSc (dao gamma ) trong cac ca md khong chay mau dd'i vdi cac khdi u nam sau trong nao, ma benh nhan khong can phai gay me, cd the di lai dugc ngay sau ca mo,... Nam 2005, mot thie't bi "dao gamma" nhu vay da dugc dua vao su dung d Viet Nam (tai Benh vien Trudng Dai hpc Y Khoa Hue). c) Trong cong nghiep va nghien cuu khoa hoc Phuang phap nguyen tu danh dau duge dung rdng rai de theo ddi su di chuyen ciia nudc mat, nude ngam, kiem tra toe do tham qua de, dap, tham dd di u khf, nghien cuu ca che etia eae phan ling phue tap va do dae cac hang sd hoa If. Tia y vdi kha nang dam xuyen manh cho phep kiem tra do dae kbit eiia be tdng va cae vat lieu ket khdi, phat hien cae khuyet tat, nut, gl y nam sau trong vat lieu ma khdng phai pha mau. Nang lugng eiia tia phdng xa ed the gay ra nhieu bien ddi hoa hgc, bie'n tfnh nhieu vat lieu tao ra cae vat lieu mdi, vdi nhung tfnh chat cue ki ddc dao. Cae phuang phap hat nhan ed kha nang phat hien tap chat d ndng do rat nho (10-9 - 10-8), da lam thay ddi dang ke dien mao eiia Hoa hgc phan tich hien dai. Phan tieh ddng vj cho phep xac djnh tudi eiia mSu dat da hoac ml u hoa thach,... 16 „1 si; CHUYEN DONG CUA ELECTRON TRONG NGUYEN TU. OBITAN NGUYEN TU • Trong nguyen tiir, electron chuyen dong nhirthe nao ? Sir chuyen dong cua electron co giong sir chuyen dong cua cac vat the ldn hay khong ? • The nao la obitan nguyen turva hinh dang cua chung ra sao ? Co nhCmg loai obitan nguyen tur nao trong nguyen tur ? I - Sir CHUY£N DONG CUA ELECTRON TRONG NGUYEN TU 1. Mo hinh hanh tinh nguyen tir Md hinh nguyen tir cii do Ra-do-pho, Bo va Zom-mo-phen (A. Sommerfeld) de xudng. Theo md hinh nay trong nguyen tir cac electron chuyen ddng tren nhii"ng quy dao trdn hay bau due xac dinh xung quanh hat nhan, nhu cac hanh tinh quay quanh mat trdi (hinh 1.6). Do dd md hinh nay cdn dugc ggi la md hinh hanh tinh nguyen tir. Tuy nhien, md hinh nay khdng phan anh diing trang thai chuyen ddng cua electron trong nguyen tir. Tit nhiing thuyet cua vat li hien dai, ta biet trang thai chuyen ddng cua electron (nhung hat vi md - nhiing hat vd cung nhd) cd nhiing khac biet ve ban chat so vdi su chuydn ddng cua nhimg vat the vi md (vat the ldn) ma ta thudng quan sat tha'y hang ngay. Md hinh hanh tinh nguyen tit cua Ro-do-pho, Bo va Zom-mo-phen cd tac dung rai ldn de'n su phat trien li thuyet cau tao nguyen tir nhung khdng My du de giai thich mgi tinh chat cua nguyen tir. Electron Hat nhan Quy dao electron Hinh 1.6. Mo hinh hanh tinh nguyen tCt cua Ra-da-pho, Bo va Zom-ma-phen 2 - HNIO;NC-A 17 2. Mo hinh hien dai ve sir chuyen dong cua electron trong nguyen tu, obitan nguyen tir a) Sir chuyen dgng ciia electron trong nguyen tu" Trong nguyen tir, cac electron chuyen ddng rat nhanh xung quanh hat nhan khdng theo mdt quy dao xac dinh nao. Gia sir chiing ta cd the chup anh electron cua nguyen tir hidro d mdt thdi diem nao dd, ndu chiing ta lai chup anh d mot thdi diem tie'p theo thi electron se d mdt vi trf khac. Ne'u chiing ta chdng hang trieu bile anh thu dugc sao cho hat nhan triing nhau thi hinh anh thu dugc b^ng each lap ghep cd the gidng nhu mdt dam may dugc tao thanh tii mdt sd rat ldn cac da'u cham, mdi da'u cham bieu di6n mdt vi tri ciia electron xung quanh hat nhan. Ddi vdi nguyen tir hidro, su chuyen ddng cua electron cd the hinh dung nhu mdt dam may tich dien am. Ve mat If thuyet, khdng cd dudng bien ro net cua dam may tfch dien, nhung thuc te cd the ve thanh mdt mat cong bao quanh hau nhu toan bd dien tich cua dam may. b) Obitan nguyen tii Vung khdng gian bao quanh hat nhan nguyen tir chiia hau nhu toan bd dien tich cua dam may dugc ggi la obitan nguyen tir. Tuy nhien, mat do dien tfch khong ddng deu trong khdng gian nay. Mat do dien tfch day dac hon d gan hat nhan. May electron cua nguyen tir hidro d trang thai co ban hau nhu tap trung trong mot vung khdng gian cd dang hinh cau ban kinh trung binh 0,053 nm (hinh 1.7). Nhu vay : Obitan nguyen tic Id khu vuc khdng gian xung quanh hat nhdn md tai do xdc sudt co mat (xdc sudt tim thdy) electron khodng 90%. Obitan nguyen tir dugc kf hieu la AO (Atomic Orbital). Hinh 1.7. Dam may electron hinh cau cCia nguyen tCt hidro 18 2 - HN10/NC-8 De cho tien Igi va don gian, ngudi ta cung cd the bieu diSn obitan nguyen tir hidro bang mdt mat cong net li6n thay cho hinh anh cac da'u cha'm (hinh 1.8). Hinh 1.8. BiSu di§n obitan nguyen tH hidro mot each dan gian II - HiNH DANG OBITAN NGUYEN TU Khi chuyen ddng trong nguyen tir, cac electron cd the chiem nhiing miic nang lugng khac nhau dac trung cho trang thai chuyen ddng cua nd. Nhiing electron chuyen ddng gan hat nhan hon, chiem nhiing miic nang lugng thap hon tiic la d trang thai ben hon, nhiing electron chuyen ddng d xa hat nhan cd nang lugng cao hon. Dua tren su khac nhau ve trang thai cua electron trong nguyen tir, ngudi ta phan loai thanh cac obitan s, obitan p, obitan d va obitan f. Hinh dang cac obitan s va p dugc bieu di6n tren hinh 1.9 va 1.10. AOn AOp„ AOp, Hinh 1.9. Obitan s Hinh 1.10. Cac obitan p^ , Py va p^ co dang hinh so tam noi Tir hinh anh cac obitan nguyen tir, chung ta thay : Obitan s cd dang hinh cau, tam la hat nhan nguyen tir. Obitan p gdm 3 obitan p^, Py va p^ cd dang hinh sd tam ndi. Mdi obitan cd su dinh hudng khac nhau trong khdng gian, chang han obitan p^ dinh hudng theo true X, obitan Py dinh hudng theo true y,... Obitan d,fc6 hinh dang phiic tap hon. 19 BAI TAP 1. Obitan nguyen tu" hidro 6 trang thai co ban cd dang hinh cau va c6 ban kfnh trung binh la A. 0,045 nm. C. 0,098 nm. B. 0,053 nm. D. 0,058 nm. Chgn dap an dCing. 2. Obitan Py cd dang hinh sd tam noi A. dugc djnh hudng theo true z. C. dugc djnh hudng theo true x. B. dugc djnh hu6ng theo true y. D. khong djnh hudng theo true nao. Chgn dap an dung. 3. Dap an nao diing trong cac dap an sau day ? Trong nguyen tu" hidro electron thudng dugc tim thay A. trong hat nhan nguyen tilr. B. ben ngoai hat nhan, song 6 gan hat nhan vi electron bj hut bdi hat proton. C. ben ngoai hat nhan va thudng d xa hat nhan, vi the tfch nguyen tCf la may electron ciia nguyen tii' d6. D. ca ben trong va ben ngoai hat nhan, vi electron luon dugc tim tha'y 6 bat ki ch5 nao trong nguyen tu". 4. Co the mo ta sU chuyen dgng cua electron trong nguyen tu" bang cac quy dao chuyen dgng khong ? Tai sao ? 5. Theo If thuyet hien dai, trang thai chuyen dgng ciia electron trong nguyen tu" dUOc mo ta bang hinh anh gi ? 6. Trinh bay hinh dang ciia cac obitan nguyen tCf s, p va neu rd sU djnh hudng khac nhau cua chiing trong khong gian. 20 LUYEN TAP VE : THANH PHAN CAU TAO NGUYEN TU KHOI LUONG CUA NGUYEN TU OBITAN NGUYEN TU • Cung CO kien thiirc ve thanh phan cau tao nguyen tur, hat nhan nguyen tur, kich thirdc, khoi luong, dien tich cua cac hat. • Hieu khai niem nguyen to hoa hoc, ki hieu nguyen tur, dong vj, nguyen tur khoi, nguyen tur khoi trung binh, obitan nguyen tur. • Ren luyen kT nang xac djnh so electron, proton, notron va nguyen tur khoi khi biet ki hieu nguyen tur. A - KIEN THllrC CAN NAM VOTNG 1. Nguyen tir dmpc tao nen boi electron va hat nhan. Hat nhan duoc tao nen boi proton va notron qe = 1- ; m^ « 0,00055 u. qp= 1+ ; mp« 1 u. q„ = 0 ; m^ « 1 u. 2. Trong nguyen tir, so proton = so electron Sd khdi A = Z -I- N. Nguyen tir khdi dugc coi nhu bang tdng sd cac proton va cac notron (gSn dung). Nguyen tir khdi cua mdt nguyen td cd nhidu ddng vi la nguyen tir khdi trung binh cua cac ddng vi, cd tfnh den ti le phan tram so nguyen tir cua mdi ddng vi. Nguyen td hoa hgc gdm nhiing nguyen tir cd cung dien tfch hat nhan. Cac ddng vi cua mgt nguyen to hoa hgc la cac nguyen tir cd cung sd proton, khac sd notron. 3. So hieu nguyen tirZ va so khoi A dac trung cho nguyen tir Kf hieu nguyen tu 2 ^• 4. Obitan nguyen tir - Chuyen ddng cua electron trong nguyen tir dugc md ta bang hinh anh cua cac obitan nguyen tir. 21 - Obitan nguyen tir la khu vuc khdng gian xung quanh hat nhan ma tai dd xac sua't cd mat (hay xac suat tim tha'y) electron khoang 90%. Thi du : Obitan cua nguyen tir hidro la mdt khdi cau cd ban kfnh 0,053 nm. Trong the tfch khdi cau nay tap trung khoang 90% xac suat cd mat (hay xac sua't tim thay) electron xung quanh hat nhan. - Cac obitan p^, Py, p^ (dugc viet la AO-p^, AO-py, AO-p^) cd dang hinh sd tam ndi, dinh hudng theo 3 true x, y va z cua he toa do De-cac. B - BAI TAP 1. Mgt nguyen td ciia nguyen td X c6 75 electron va 110 nOtron. Hoi kf hieu nguyen ti^r nao sau day la cua nguyen to X ? A I85v . D "ISSY . r 185Y • n ^Sy 2. Nguyen td nao sau day chda ddng thdi 20 nOtron, 19 proton va 19 electron ? A f-jC\ ; B. 39K . C. t^Ar ; D. ^gCa. 3. Theo sd lieu 6 bang 1.1 bai 1. Hay tfnh : a) Khdi lugng (g) cua nguyen tCr nito (gom 7 proton, 7 natron, 7 electron). b) Tl sd khdi luong cua electron trong nguyen tCr nito so vdi khdi lugng cua toan nguyen tif. 4. Biet rang nguyen td agon c6 ba dong vi khac nhau, Crng vdi sd khdi 36, 38 va A. Phan tram sd nguyen tircija cac dong vj tUdng dng Ian lugt bang : 0,34% ; 0,06% va 99,6%. Tfnh sd khdi cua dong vj A cua nguyen td agon, bie't nguyen tCr khdi trung binh cua agon bang 39,98. 5. Nguyen td Mg c6 ba dong vj dng vdi thanh phan phan tram nhu sau : Dong vj 24Mg 25Mg 26Mg 78,99 10,00 11,01 a) Tfnh nguyen tCr khdi trung binh cua Mg. b) Gia sCr trong hon hgp n6i tren c6 50 nguyen tCr 25Mg, thi sd'nguyen tCr tUOng dng cua hai dong vj con lai la bao nhieu ? 22 Mi ~6 LOP VA PHAN LOP ELECTRON • Trong nguyen tur, cac electron difdc phan bo nhi/the nao ? • The nao la ldp electron, phan ldp electron ? • Co bao nhieu obitan nguyen tur trong mot ldp electron va trong mot phan Idp electron ? I - LOP ELECTRON Trong nguyen tir, cac electron dugc sap xep thanh ttmg ldp, cac ldp dugc sap xep tir gan hat nhan ra ngoai. Cac electron tren ciing mdt ldp cd ndng lugng gdn bdng nhau. NhiJng electron d ldp trong lien ket vdi hat nhan ben chat hon nhung electron d ldp ngoai. Do dd, nang lugng cua electron d ldp trong thap hon nang lugng electron d ldp ngoai. Vi vay, nang lugng cua electron chii yeu phu thudc vao sd thii tu ciia ldp. Thii tu cac ldp electron dugc ghi bang cac sd nguyen n = 1, 2, 3, ..., 7. n=12 3 4 5 6 7 Ten ldp : K L M N O P Q Theo trinh tu sap xep tren, ldp K (n = 1) la ldp gan hat nhan nhat. Nang lugng cua electron tren ldp nay la thap nhat. Su lien kei giua electron tren ldp nay vdi hat nhan la ben chat nhat, rdi tie'p theo la nhiing electron cua ldp iing vdi n ldn hon cd nang lugng cao hon. II - PHAN LOP ELECTRON Mdi ldp electron phan chia thanh cac phan ldp dugc kf hieu bang cac chii cai vie't thudng : s, p, d, f, ... Cac electron tren cung mdt phan ldp cd ndng lugng bdng nhau. 23 Sd phan ldp trong mdi ldp bang so thii tu cua ldp dd. Ldp thii nhat (ldp K) cd 1 phan ldp, dd la phan ldp Is. Ldp thu" hai (ldp L) cd 2 phan ldp, dd la cac phan ldp 2s va 2p. Ldp thu- ba (ldp M) cd 3 phan ldp, dd la cac phan ldp 3s, 3p va 3d. Ldp thii' tu (ldp N) cd 4 phan ldp, dd la cac phan ldp 4s, 4p, 4d va 4f. Ldp thir n cd n phan ldp electron. Tuy nhien, tren thuc te vdi hon 110 nguyen td da bidt, chi cd sd electron dien vao bd'n phan ldp s, p, d va f. Cac electron d phan ldp s dugc ggi la cac electron s, d phan ldp p dugc ggi la cac electron p,... III - SO OBITAN NGUYEN TU TRONG MOT PHAN LOP ELECTRON Trong mdt phan ldp, cac obitan cd ciing miic nang lugng, chi khac nhau su dinh hudng trong khdng gian. Sd va dang obitan phu thudc vao dac diem cua m6i phan ldp electron : - Phdn lap s : Chi cd 1 obitan, cd ddi xiing cdu trong khdng gian (hinh 1.9). - Phdn lap p : Co 3 obitan p^, Py, p^ dinh hudng theo cac true x, y va z (hinh 1.10). - Phdn lap d : Co 5 obitan, dinh hudng khac nhau trong khdng gian. - Phdn Idpf: Cd 7 obitan, ciing dinh hudng khac nhau trong khdng gian. Nhu vay : Sd obitan trong cac phan ldp s, p, d, f tuong ling la cac sd le : 1, 3, 5,7. IV - SO OBITAN NGUYEN TU TRONG MOT LOP ELECTRON Sd obitan trong ldp electron thii n la n^ obitan : - Ldp K (n = 1) cd P = 1 obitan, dd la obitan Is. - Ldp L (n = 2) cd 22 = 4 obitan, gdm 1 obitan 2s va 3 obitan 2p. - Ldp M (n = 3) cd 32 = 9 obitan, gdm 1 obitan 3s, 3 obitan 3p va 5 obitan 3d. - Ldp N (n = 4) cd 42 = 16 obitan, gdm 1 obitan 4s, 3 obitan 4p, 5 obitan 4d va 7 obitan 4f. 24 BAI TAP 1. Cac obitan trong mot phan Idp electron A. CO cung sudjnh hudng trong khong gian. B. c6 cung miic nang lugng. C. khac nhau ve miic nang lugng. D. CO hinh dang khong phu thuoc vao dac diem m6i phan I6p. Hay chgn dap an diing. 2. The nao la Idp va phan Idp electron. Su khac nhau gida Idp va phan I6p electron ? 3. Hay cho bie't ten cua cac Idp electron dng vdi cac gia trj cua n = 1, 2, 3, 4 va cho bie't cac I6p do Ian lugt c6 bao nhieu phan I6p electron ? 4. Hay cho bie't sd phan Idp electron, sd obitan c6 trong Idp M va N. 5. Ve hinh dang cac obitan Is, 2s va cac obitan 2px, 2py, 2p^. 25 (Bdi NANG LUONG CUA CAC ELECTRON TRONG NGUYEN TU CAU HiNH ELECTRON NGUYEN TU • Trong nguyen tur, cac electron chiem nhOmg mure nang luong nao ? Trinh tir sap xep cac mure nang luong nay ra sao ? • Viec phan bo cac electron trong nguyen tur tuan theo nhCmg nguyen li va quy tac nao ? • Cau hinh electron nguyen tur la gi ? Cach vie't cau hinh electron nguyen tur nhir the nao ? I - NANG LUONG CUA ELECTRON TRONG NGUYEN TU 1. Mure nang Impng obitan nguyen tur Trong nguyen tir, cac electron tren mdi 7s M obitan cd mgt mdc nang lugng xac dinh. Ngudi ta ggi miic nang lugng nay Rs • la mice ndng lugng obitan nguyen tic 5s (miic nang lugng AO). Cac electron tren cac obitan khac nhau 4s cua cung mdt phan ldp cd nang lugng nhu nhau. Thf du : IJhg vdi n = 2, ta cd 3s 2 phan ldp la 2s va 2p. Phan ldp 2s chi cd mdt obitan 2s, cdn phan ldp 2p cd 3 obitan : 2pjj, 2py, 2p2. Cac electron 2s ciia cac obitan p trong phan ldp nay tuy cd su dinh hudng trong khdng gian khac nhau, nhung chiing cd cimg miic nang lugng AO. o Is Trat tir cac muc nang luong obitan nguyen tir m'£ m'£ bp • • 4p 3p 2p 6d • •• • 5d • •• • 4d 3d • •• • 5f •••••• • 4f •••••• • 32 t 32 I 18 Thuc nghiem va If thuyet cho tha'y khi sd hieu nguyen tir Z tang, cac miic nang lugng AO tang dan theo trinh tu sau : Hinh 1.11. Moi quan he ve mUc nang luang cCia cac obitan trong nhUng phan ldp khac nhau 1 s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d... 26 Tir trinh tu miic nang lugng AO tren cho tha'y khi dien tfch hat nhan tang cd su chin mice nang lugng, muc 4s trd nen thap hon 3d, mdc 5s thap hon 4d, 6s thap hon 4f, 5d,... II - CAC NGUYEN Ll VA QUY TAC PHAN B 6 ELECTRON TRONG NGUYEN TU Su phan bd cac electron trong nguydn tir tuan theo nguyen If Pau-li, nguyen If viing ben va quy tac Hun (F.Hund). 1. Nguyen li Pau-li a) 6 lugng tir D^ bieu di6n obitan nguyen tit mdt each don gian, ngudi ta cdn dimg d vudng nhd, dugc ggi la d lugng tic. Mdt d lugng tir dng vdi mdt AO. Thi du : IJhg vdi n = 1 chi cd mdt obitan Is, ta ve mdt d vudng. IJhg vdi n = 2 cd mdt obitan 2s va ba obitan 2p (2px, 2py va 2pj), ta ve mdt d vudng thudc phan ldp 2s va ba d vudng thudc phan ldp 2p, ba d vudng nay dugc ve li6n nhau, dd chi rang cac obitan 2p cd cung mire nang lugng AO, nhimg cao hon AO -2s (hinh 1.12a va hinh 1.12b). D Obitan : 1s 2s, 2p^, 2py, 2p2 (a) (b) Hinh 1.12. Cac 6 luang tit Ung vdi n = 1 va n = 2 . b) Nguyen li Pau-li Pau-li (Wolfgang Pauli) (1900- 1958) Trin mot obitan chi cd the cd nhieu nhdt Id hai electron vd hai electron ndy chuyen ddng tU quay khdc chieu nhau xung quanh true riing cua mdi electron. Ngudi ta bieu thi chieu tu quay khac nhau quanh true rieng cua hai electron bang 2 mui ten nhd : Mdt miii ten cd chieu di len, mdt mui ten cd chieu di xudng. Trong mgt obitan da cd 2 electron, thi 2 electron dd ggi la electron ghep ddi (hinh 1.13a). Khi obitan chi cd mdt electron thi electron dd ggi la electron ddc thdn (hinh 1.13b). 27 n m (a) 2 electron ghep doi (b) 1 electron doc than Hinh 1.13. Electron ghep doi va electron doc than c) So electron tdi da trong mgt Idp va trong mgt phan Idp - Sd electron tdi da trong mgt lap electron : Ta da bidt ldp n cd n2 obitan. M5i obitan theo nguyen If Pau-li cd tdi da 2 electron. Do dd : Ldp n cd tdi da 2 r? electron. - Sd electron tdi da trong mdt phdn lap electron : Cung theo nguySn If Pau-li, ta cd the biet dugc sd elecUon tdi da Uong mdt phan ldp. Phan ldp s chi cd mot obitan, vay chi cd tdi da 2 electron. Phan ldp p cd 3 obitan nen cd tdi da 6 electron, tuong tu phan ldp d cd tdi da 10 electron, phan ldp f cd tdi da 14 electron. Ta cd the bieu diSn sd electron tdi da trong cac phan ldp bang cac d lugng tir tren hinh 1.14. n n n (a) (b) n n n t; n \m ninitiinin (c) (d) Hinh 1.14. So electron to'i da trong cac phan ldp (a) Phan ldp s ; (b) Phan lop p ; (c) Phan ldp d ; (d) Phan ldp f. Mdt each khac, de bieu di6n trang thai electron cua obitan Is chiia 2 electron ta dung kf hieu : ls2. O day, so 1 diing ben trai chi ldp n = 1, chii s chi obitan s, sd 2 d phfa tren ben phai chi sd electron cd chda trong obitan Is. Gia sir ph^n ldp 2p cd 6 electron, ta vie't: 2p6. Cac phan ldp : s2, p6, d^o, f ^4 cd du sd electron tdi da ggi la phdn lap bao hoa. Cdn phan ldp chua du sd electron tdi da ggi la phdn lap chua bao hod. Thf du cac phan ldp s^, p3, d^, fi2... 2. Nguyen li vung ben (J trgng thdi ca bdn, trong nguyin tu cdc electron chiim ldn lu0 nhiing obitan CO muc ndng lugng tic thdp di'n cao. 28 Thidu : Nguyen tu hidro (Z = 1) cd 1 electron, electron nay se chie'm obitan Is (AO-ls) cd miic nang lugng tha'p nhat. Do dd cd the bieu diSn su phan bd electron cua nguyen tir hidro la : Is^; Bieu di6n bang d lugng tir la \~\~\ Nguyin tic heli (Z = 2) cd 2 electron. Theo nguyen If Pau-li, hai electron nay cung chiem obitan Is cd mdc nang lugng tha'p nhat. Bdi vay su phan bd electron tren obitan ciia heli la ls2 -^ f j Nguyin tic liti (Z = 3) cd 3 electron, 2 electron trudc chiem obitan Is va da bao hoa, electron cdn lai chiem obitan 2s tiep theo cd miic nang lugng cao hon. Do dd su phan bd electron tren cac obitan cua lid la : ls22si n t 2si 1s^ Mdt each tuong tu, ta cd thd viet dugc su phan bd electron tren cac obitan cua cac nguyen td tiep theo. Thi du : Be(Z = 4): Is2 2s2 B(Z = 5): Is22s22pi 2s2 is-^ n tM 2s2 2p' 1s^ Tuy nhien, khdng nhat thie't liic nao cQng phai bieu diln cac A0-2p phai cao hon AO-2s,... vi se cdng kenh. Ngudi ta chi bidu didn su cao, thap cua cac d lugng tir khi can thd hien mdc nang lugng khac nhau ciia tirng phan ldp electron. 3. Quy tac Hun Trong cung mgt phdn lap, cdc electron se phdn bd tren cdc obitan sao cho sd electron ddc thdn Id tdi da vd cdc electron ndy phdi cd chieu tu quay gidng nhau. Thf du su phan bd electron tren cac obitan cua nguyen tir cacbon, nito nhu sau : 2s2 2p^ N (Z = 7) : n tiimt C (Z - 6) : n n^ 1s^ 1s^ 2s2 2p^ Cac electron ddc than trong mdt nguyen tir dugc kf hieu bang cac miii ten cting chieu, thudng dugc viet hudng len tren. 29 Ill - CAU HINH ELECTRON NGUYEN TU 1. Cau hinh electron nguyen tur Cdu hinh electron nguyin tu: bieu diin su phdn bd electron trin cdc phdn lopthudc cdc lap khdc nhau. Quy udc cdch vii't cdu hinh electron nguyen tic : - Sd thii tu ldp electron dugc vie't bang cac chii sd (1, 2, 3...) - Phan ldp dugc kf hieu bang chii cai thudng (s, p, d, f). - So electron dugc ghi bang chi so d phfa tren, ben phai kf hieu cua phan ldp (S2, p2,...). Cdch viet cdu hinh electron nguyin tic : - Xac dinh sd electron cua nguyen tir. - Cac electron dugc phan bd theo thii tu tang dan cac miic nang lugng AO, theo cac nguyen If va quy tac phan bd electron trong nguyen tir. - Viet cau hinh electron theo thd tu cac phan ldp trong mdt ldp va theo thii til cua cac ldp electron. Thi du : Na (Z = 11) cd 11 electron. Cau hinh electron cua Na nhu sau : ls2 2s22p63s' Fe (Z = 26) cd 26 electron. Do cd su chen mure nang lugng, cac electron dugc phan bd nhu sau : Is22s22p63s23p64s23d6 Sau dd phai sap xep cac phan ldp theo tiing ldp : ls22s22p63s23p63dMs2 Hoac viet ggn la : [Ar] 3dMs2. [Ar] la kf hieu cau hinh electron nguyen tir cua nguyen td agon, la khf hiem gan nhat diing trudc Fe. 2. Cau hinh electron nguyen tir cua mot so nguyen to Dua vao cac nguyen If va quy tac neu d tren ta cd the xay dung ca'u hinh electron nguyen tir cua cac nguyen td khac. Dudi day la cau hinh electron nguyen tir cua 20 nguyen td dau tien trong bang tuan hoan (bang 1.2). 30 Bang 1.2 CSlu hinh electron nguyen tu cua 20 nguyen to dau tien trong bang tuan hoan Nguyen td Cau binh electron Cau hinh electron viet dudi dang 6 lugng tu 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca 1s^ 1S2 1s2 2s1 1s2 2s2 1s2 2s2 2pi 1s2 2s2 2p2 1s2 2s2 2p3 1s2 2s2 2p4 1s2 2s2 2p5 1s2 2s2 2p6 1s2 2s2 2pS3s^ 1s2 2s2 2p6 3s2 1s2 2s2 2p6 3s2 3pi 1s2 2s2 2pS3s2 3p2 1s2 2s2 2pS3s2 3p3 1s2 2s2 2pS3s2 3p'* 1s2 2s2 2pS3s2 3p5 1s2 2s2 2p6 3s2 3p8 1s2 2s2 2pS3s2 3pS4s^ 1s2 2s2 2pS3s2 3pS4s2 m Bl Gam [IBS n ti t ti ti r t ti ti t t t t ti ti t t ti i ti ti t ti ti ti ti ti nlBilltiltiltiim tHrulltiltiiniBil ti ti ti ti fi ti t ti ti ti ti ti ti t t ti ti ti ti ti ti tt t i ti ti ti ti ti ti t t ti ti ti ti ti ti ti ti t ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti ti 31 3. Dac diem cua lop electron ngoai ciing Cac electron d ldp ngoai ciing quyet dinh tfnh cha't hoa hgc cua mdt nguyen td. a) Ddi vdi nguyen tir cua cac nguyen td, sd electron ldp ngoai cung tdi da la 8. Cac nguyen tir cd 8 electron ldp ngoai cung deu rat bdn viing, chiing hau nhu khdng tham gia vao cac phan dng hoa hgc. Dd la cac nguyen tir khf hiem (trii He cd sd electron ldp ngoai cung la 2). b) Cac nguyen tir cd 1, 2, 3 electron d ldp ngoai cung la cac nguyen tir kim loai (trii H, He va B). c) Cac nguyen tu cd 5, 6, 7 electron d ldp ngoai cimg thudng la cac nguyen ttr phi kim. d) Cac nguyen tir cd 4 electron d ldp ngoai ciing cd the la nguyen tir kim loai hay phi kim. BAI TAP 1. Hay ghep cau hinh electron d trang thai cO ban vdi nguyen td thich hgp Cau hinh electron Nguyen tu" A. 1s22s22p5 a. Cl B. 1s22s22p4 b. S C. 1s22s22p63s23p4 c. O D. 1s22s22p63s23p5 d. F 2. Su phan bd electron trong nguyen td tuan theo nhdng nguyen If va quy tac gi ? Hay phat bieu cac nguyen If va quy tac d6. Lay thi du minh hoa. 3. Tai sao trong so do phan bd electron cua nguyen tii cacbon (C : 1 s22s22p2), phan I6p 2p lai bieu diin nhu sau : f f 4. Hay vie't cau hinh electron cua cac nguyen td co Z = 20, Z = 21, Z = 22, Z = 24, Z = 29 va cho nhan xet cau hinh electron ciia cac nguyen td d6 khac nhau the nao ? 5. Hay cho biet sd electron Idp ngoai cung cua cac nguyen td H, Li, Na, K, Ca, Mg, C, Si, 0. 6. Cau hinh electron nguyen tCr cua cac nguyen td K (Z = 19) va Ca (Z = 20) c6 dac diem gi ? 7. Viet cau hinh electron cua F (Z = 9), Cl (Z = 17) va cho bie't khi nguyen td cua chiing nhan them 1 electron thi Idp electron ngoai cung c6 dac diem gi. 32 M- o \uYEN TAP CHUONG I • Cung CO cac kien thiirc : - Thanh phan cau tao nguyen tCr, dac diem cac hat cau tao nen nguyen tCf. - Nguyen to hoa hoc, nhGtng dac trung cua nguyen to hoa hoc - Cau true vd nguyen tCt. • Van dung li thuyet de lam mot so dang bai tap co ban. A - NHOTNG KIEN THQC CAN NAM VOTNG Kfch thudc, khdi lugng nguyen tii Nguyen tis Hat nhan nguyen td^ V6 nguyen td -Obitan nguyen td "-Proton (p) - Notron (n) - • Electron (e) - -Dien tfch : 1 + -Khdi lugng : lu -Dien tich : 0 -Khdi lugng : 1u -Dien tich : 1- -Khdi lugng: 5,5.10 " 4 u C§'u true v6 nguyen ti!f Ldp electron • Phan I6p electron Su phan bd electron -Gom cac electron c6 nang lugng gan bang nhau -Ki hieu : n= 1 23456 7 K L M N O P Q _Sd obitan : n2 pGom cac electron c6 nang lugng bang nhau - -Kf hieu : s p d f -Sd obitan : 13 5 7 -Nguyen If Pau-li -Nguyen If vdng ben -Quy tac Hun Trat tu cac mdc nang lugng Nguydn to ho^ hoc -Cau hinh electron nguyen td -Dac diem Idp electron ngoai cung. Dien tich hat nhan (Z+) : Z = sd p = sd e -So khdi (A): A = Z + N -^°"9^ ! - aA + bB Nguyen td khdi trung binh : A 100 3 - HN10/NC-A 33 B - BAI TAP 1. Day nao trong cac day sau day gdm cac phan Idp electron da bao hoa ? • > A. s1, p3, d^, f12; B. s2, p5, cjS, fi3; C. s2, p4, d^o, fii ; D. s2, p6, dio, f!'*. 2. Cau hinh electron d trang thai cO ban cua nguyen td kim loai nao sau day c6 electron dgc than 6 obitan s ? A. Crom ; B. Coban ; C. Sat; D. Mangan ; E. Niken. 3. Mdc nang lugng cua cac obitan 2px, 2py va 2p2 c6 khac nhau khong ? Vi sao ? 4. Hay cho bie't sd electron tdi da : a) Trong cac Idp K, L, M, N. b) Trong cac phan Idp s, p, d, f. 5. Su phan bd cac electron vao m6i obitan nguyen td d trang thai cd ban sau cd dugc vie't dung khong ? Hay giai thich. n ft M a b c Cac obitan ns it n t t I Cac obitan np 6. Khi sd hieu nguyen tii Z tang, trat tU cac mdc nang lugng AO tang dan theo chieu tii trai qua phai c6 dung trat tu nhu day sau khdng ? Is 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 6s 5d 6p 7s 5f 6d... Neu sai, hay sda lai cho diing. 7. Viet cau hinh electron nguyen td cua cac nguyen td c6 Z = 15, Z = 17, Z = 20, Z = 21, Z = 31. 8 Nguyen td Fe c6 Z = 26. Hay viet cau hinh electron cua Fe. Neu nguyen td Fe bi mat hai electron, mat ba electron thi cac cau hinh electron tUOng dng se nhU the nao ? 34 3 - HN10/NC-B Chuang BANG TUAN HOAN CAC NGUYEN TO HOA HOC VA DINH LUAT TUAN HOAN m m y Cac nguyen td hoa hgc du'Oc sap xep vao bang tuan hioan theo nhiing nguyen tac nao ? y Cau hinh electron nguyen td cua nguyen to' hoa hgc c6 mdi quan he nhu" the nao vdi vj tri cua chiing trong bang tuan hoan ? 1/ Tfnh chat cac nguyen to trong bang tuan hoan bien doi nhu" the nao ? ^ Bang tuan hoan cd y nghia gi ? Men-de-le-ep (fl. H. MeHfleneeB) (1834-1907) 35 ^di 9 BANG TUAN HOAN CAC NGUYEN TO HOA HOC • Bang tuan hoan diroc xay dung tren nguyen tac nao ? • Bang tuan hoan diroc cau tao nhirthe nao ? I - NGUYEN TAC SAP XEP CAC NGUYEN TO TRONG BANG TUAN HOAN Cac nguyen td hoa hgc dugc xep vao mdt bang, ggi la bang tuan hoan, dua tren cac nguyen tac sau : - Cac nguyen td dugc xep theo chitu tang dan cua dien tich hat nhan nguyen tir. - Cac nguyen td cd ciing sd ldp electron trong nguyen tit dugc xep thanh mdt hang. - Cac nguyen td cd cimg so electron hoa tri**) trong nguyen tvr dugc xep thanh mgt cdt. li - CAU TAO BANG TUAN HOAN 1.0 nguyen to Mdi nguyen to hoa hgc dugc xep vao mdt d cua bang, ggi la d nguyen td. Sd thii tu cua d dung bang sd hieu nguyen tir cua nguyen td dd. Thi du : O nguyen td cua hidro va cua nhdm. Ki hieu hoa hoc Ten nguyen to So hieu nguyen Ll r 1 2 20 Hidro - J 1- 1 -1 +1 Nguyen tuf khoi trung binh Dp am dien Cau hinh electron S5 oxi hoa Kl hieu hoa hoc Ten nguyen to So hieu nguyen > ^ l 1 gl Nhdm [Ne]3s'3p' .,.3 Cf Nguyen tuf khoi trung binh Dp am dien Cau hinh electron So oxi hoa (*) Electron hoi tri la niiimg electron co kiia nang tliam gia iiinii tiianli lien k6i hoa iioc. Ciiung thaong nam b Icip ngoai ciing hoac b ca phan ldp sat Idfp ngoai ciing neu phan 16p do chua bao hoa. 36 2. Chu ki Chu ki la ddy cdc nguyin td md nguyin tic cua chung cd cimg sd lap electron, dugc xip theo chieu diin tich hat nhdn tdng ddn. Bang tuan hoan gdm 7 chu ki dugc danh sd td 1 de'n 7. Sd thd tu ciia chu ki trung vdi sd ldp electron cua nguyen tir cac nguyen to trong chu ki dd. Gidi thieu cdc chu ki : Chu ki 1 : Gdm 2 nguyen td la H (Z = 1) va He (Z = 2). Nguyen tir cua chiing cd mdt ldp electron (n = 1) va cac electron dugc phan bd vao phan ldp s nhu sau : H(lsi) vaHe(ls2). Chu ki 2 : Gdm 8 nguyen td, td Li (Z = 3) de'n Ne (Z = 10). Nguyen tu cua chung cd 2 ldp electron (n = 2) va cac electron dugc phan bd vao cac ldp nhu sau : Li (ls2 2s>) cho de'n Ne (ls2 2s2 2p6). Chu ki 3 : Gdm 8 nguyen td, tir Na (Z = 11) de'n Ar (Z = 18). Nguyen tu cua chung cd 3 ldp electron (n = 3) va cac electron dugc phan bd vao cac ldp nhu sau : Na (1 s2 2s2 2p6 3s') cho de'n Ar (1 s2 2s2 2p6 3s2 3p6). Chu ki 4 : Gdm 18 nguyen td td K (Z = 19) de'n Kr (Z = 36). Nguyen tu cua chung cd 4 ldp electron (n = 4). Viec phan bd electron d chu ki nay cd dac diem la chua phdn bd'vdo phdn lap 3d ma phan bd vao phan ldp 4s cho dii 2 electron d nguyen tukim loai ki6m K (Z = 19) : ls2 2s2 2p6 3s2 3p6 4s' vakim loai kiem tho Ca (Z = 20) : ls2 2s2 2\P 3s2 3p6 4s2, sau dd mdi phan bd electron tiep tuc vao phan ldp 3d tu 1 de'n 10 electron cho cac nguyen tu cua 10 nguyen td kim loai chuyen tie'p (tu Sc (Z = 21) de'n Zn (Z = 30)). Tiep theo la su phan bd electron vao phan ldp 4p cua cac nguyen tu 6 nguyen td td Ga (Z = 31) cho de'n Kr (Z = 36). Chu ki 5 : Gdm 18 nguyen td, tir Rb (Z = 37) de'n Xe (Z = 54), su phan bd electron cung difin ra tuong tu chu ki 4. Chu ki 6 : Gdm 32 nguyen td, td Cs (Z = 55) de'n Rn (Z = 86), su phan bd electron difin ra phdc tap hon. Chu ki 7 : Bat dau tir nguyen td Fr (Z - 87) de'n nguyen td cd sd thd tu 110 (Z = 110). Day la mdt chu ki chua hoan thanh. Phdn loai chu ki : Cac chu kl 1, 2 va 3 la cac chu ki nhd. Cac chu ki 4, 5, 6 va 7 la cac chu ki ldn. 37 3. Nhom nguyen to Nhdm nguyin td la tap hgp cdc nguyin td md nguyin tu' co cdu hinh electron tuang tu nhau, do dd cd tinh chdt hod hgc gdn gid'ng nhau vd dugc xi'p thdnh mgt cot. Nguyen tir cac nguyen td trong cung mdt nhdm cd sd electron hod tri bang nhau va bang sdthic tu cua nhdm (trtr mdt sd ngoai le). Bang tuan hoan cd 18 cot dugc chia thanh 8 nhdm A danh sd tir IA de'n VIIIA va 8 nhdm B danh sd td IB den VIIIB. Mdi nhdm la mdt cot, rieng nhdm VIIIB gdm 3 cdt. Ngoai each chia cac nguyen td thanh nhdm, ngudi ta cdn chia chung thanh cac khdi nhu sau : • Khdi cac nguyen td s gdm cac nguyen td nhdm IA va nhdm IIA. Nguyin td s Id nhicng nguyin td md nguyin tic cd electron cudi ciing dugc dien vdo phdn lap s. Thidu : Na (Z = 11) : ls2 2s2 2p6 3si ; K (Z = 19) : ls2 2s2 2p6 3s2 3p6 4si Mg (Z = 12) : ls2 2s2 2p6 3s2 ; Ca (Z = 20) : ls2 2s2 2p6 3s2 3p6 4s2 • Khdi cac nguyen td p gdm cac nguyen td thudc cac nhdm td IIIA de'n VIIIA (trd He). Nguyen tdp Id nhiing nguyin td md nguyin tic co electron cudi cung dugc dien vdo phdn lap p. Thidu : O (Z = 8) : ls2 2s2 2p4 ; S (Z = 16) : ls2 2s2 2p6 3s2 3p4 Ne (Z = 10) : ls2 2s2 2p6 ; Ar (Z = 18) : ls2 2s2 2p6 3s2 3p6 Cdc nhdm A bao gdm cdc nguyin td s vd nguyin td p. • Khdi cac nguyen to d gdm cac nguyen td thudc cac nhdm B. Nguyin tdd la cdc nguyin tdmd nguyen tic co electron cudi cung dugc dien vdo phdn lap d. • Khdi cac nguyen td f gdm cac nguyen td xep thanh hai hang d cud'i bang. Chung gdm cd 14 nguyen to hg Lantan (tir Ce (Z = 58) de'n Lu (Z = 71)) va 14 nguyen td hg Actini (td Th (Z = 90) de'n Lr (Z = 103)). Nguyin tdfld cdc nguyin td md nguyen tic cd electron cud'i cung dugc dien vdphdn lap f. Cdc nhdm B bao gdm cdc nguyin td d vd nguyin tdf. 38 BAI TAP 1 • Nguyen td cac nguyen td xep d chu ki 6 c6 sd Idp electron trong nguyen td la : A. 3. B. 5. C. 6. D. 7. Chgn dap an dung. 2. So nguyen td trong chu ki 3 va chu ki 5 la A. 8va18 . B. 18va8 . C. 8 va 8. D. 18va18. Chgn dap an diing. 3. Trong bang tuan hoan cac nguyen td, sd chu ki nho va chu ki I6n la A. 3 va 3. B. 3 va 4. C. 4 va 4. D. 4 va 3. Chpn dap an dung. 4. So hieu nguyen td ciia cac nguyen td trong bang tuan hoan cho ta bie't nhdng thong tin gi ? 5. Vi sao chu ki 2 va chu ki 3, moi chu ki c6 8 nguyen td ? 6. a) Nhom nguyen td la gl ? b) Cac nguyen td s, p, d, f thugc nhdng nh6m nao trong bang tuan hoan ? 7. Viet cau hinh electron nguyen td cua cac nguyen td td Z = 1 de'n Z - 20. 8. Viet cau hinh electron nguyen td cua cac nguyen td selen (Z = 34), kripton (Z = 36) va xac dinh vj tri cua chung trong bang tuan hoan. fit lieu_ DO! NET VE OI-MI-TRI l-VA-NO-VICH MEN-OE-LE-EP VA OJNH LUAT TUAN HOAN - BANG TUAN HOAN CAC NGUYEN TO HOA HOC Di-mi-tri l-va-no-vich Men-de-le-ep sinh ngay 27 thang gieng nam 1834 d thanh phd To-bon (Tobonxk) trong mot gia dinh cd 17 ngudi con, bd la hieu trudng Trudng Trung hoc. Sau khi tdt nghiep Trudng Trung hoc To-bon, ong vao hoc Trudng Oai hoc Su pham Pe-tec-bua va nam 1855 da dugc nhan buy chuang vang khi tdt nghiep. Nam 1859, Men-de-le-ep da lam viec d Ddc hai nam. Sau dd dng trd ve nudc Nga va dugc bau lam giao su cua Trudng Dai hgc KT thuat Pe-tec-bua. Hai nam sau dng 6uqc bd nhiem la giao su ciia Trudng Dai hgc Tdng hgp Pe-tec-bua. Sau 33 nam nghien cdu khoa hgc va giang day, nam 1892 Men-de-le-ep dugc bd nhiem lam phu trach khoa hgc bao tdn ciia tram can do mSu. Nam 1893, tram nay ddi thanh Vien nghien cdu khoa hgc do ludng mang ten Men-de-le-ep. 39 Ket qua boat ddng sang tao v7 dai nhat ciia Men-de-le-ep la su phat minh ra dinh luat tuan hoan cac nguyen td nam 1869, liic dd dng mdi 35 tuoi. Ngoai ra, dng cdn cd nhieu cdng trinh khac cd gia tri nhu : cac nghien cdu ve trgng lugng rieng cua dung dich nudc, dung dich ciia rugu - nudc va khai niem ve dung dich. Nhung cdng trinh nghien cdu ciia Men-de-le-ep ve dung dich la phan quan trgng ciia thuyet hien dai. Cudn "Ca sd hga hgc" la cdng trinh xuat sSc ciia Men-de-le-ep, trong dd ISn dau tien toan bd hoa hgc vd eg dugc trinh bay theg quan diem ciia dinh luat tuan hoan. Nam 1947, cudn sach dugc tai ban Ian thd 1 3. Ket hgp mdt each chat che li thuyet vdi thuc te, Men-de-le-ep ludn ludn quan tam den su phat trien cdng nghiep cua dat nudc Nga. Bang tuan hoan cac nguyen td cd anh hudng Idn de'n su phat trien ciia hoa hgc. Nd khdng nhung la su phan loai tu nhien dau tien cac nguyen td hoa hgc, cho biet cac nguyen td cd mdi lien he chat che va he thdng, ma cdn djnh hudng cho viec nghien cdu tiep tuc cac nguyen to mdi. Ngay nay, dinh luat tuan hoan vSn cdn la sgi chi din dudng va la li thuyet chii dao ciia hga hgc. Tren ca sd dd, trgng nhung nam gan day cac nguyen td sau urani da dugc dieu che nhan tao va dugc xep sau urani trong bang tuan hoan. Mdt trong cac nguyen td dd la nguyen td 101 da dugc dieu che Ian dau tien nam 1955 va ggi la mendelevi de td Idng kinh trgng nha bac hgc Nga vT dai. Viec phat minh ra dinh luat tuan hgan va bang tuan hoan cac nguyen td hoa hoc cd gia trj to Idn khdng nhung ddi vdi hoa hgc, ma ca ddi vdi triet hgc. Thuyet cau tao nguyen td d the ki XX da soi sang vao djnh luat tuan hoan va bang tuan hoan cac nguyen td, tim ra nhieu dieu mdi me sau sac han. NhOng Idi tien tri cua Men-de-le-ep "Djnh luat tuan hoan se khdng bj de doa pha vg, ma chi co su bd sung va phat trien khdng ngung", da dugc thuc te kiem chdng va xac nhan. 40 \^Nh6fn CMukr \ 1 IA 1 1,008 h i 2.20 IIA BANG TUAN HOAN IIIA IVA VA VIA VIIA [H] VIIIA 2 4,003 He HOD HeD 1 . ' CACNGUYtNTOHOAHOC is' . 1 , 5 10,81 6 12,01 7 14.007 8 15.999 9 18,998 1 0 20,18 2 3 3 6.94 L l 0,98 lA. ' 1 1 1 Z2.9S0 via 0^ Natri Mas' , 19 39,10 4 9,01 B e 1S7 Ber) 3 1 2 24,31 M g 1,31 M£«ie 2 • IIIB IVB VB VIB VIIB VIIIB IB MB D 2,04 Bo 1s%s^' 3 13 26,98 A l 161 Nh6ra [Nel 33^' 3 C 2.K is^ V 1 4 28,C9 S i 1,90 saic IffeJ3eV 4 N 3.04 Nto 1sV^^ -3,1,2.3,4,5 1 5 30.97 P 2,19 PNjtpho INelSsV -3,111,3.141,5 0 « Oxi Is^V -2,-1|-1/2,-1/3,ll2 1 6 32.06 S i.M ti/U hu;^nti (NB) & V •2,-111,21,4,6 P 3,98 Flo Is^V • 1 1 7 35,45 C l 3.16 Cto 1,1.3,141,5,7 Ne Neon 1s^^ ' 18 39.95 Ar Agon (Ne) as'Sp* 4 l \ 0^ Kail M « ' 37 65,47 R D 0,82 2 0 40,08 G 3 1,00 Canxl 2 3 8 87,62 o r 0,95 21 44,96 S o ,36 Scandl 3 3 9 88,91 Y 1,22 2 2 47,90 T i IM Titan [Ar] 3d^4s^ 2,3,4 40 91,22 Z r 133 2 3 50,94 V 1.63 Vanadi [Arl 3((^4s^ 2,131,4.5 4 1 92,91 Nb a 2 4 51,996 C r 1,66 Crom (Ar) 3(1^4s' 2,3,4,6 4 2 95,94 M o 216 25 54,94 M n 155 Mangar> [Ar| 3t^is' 2,3,4,161,6,7 43 (991 T c 1.90 2 6 55,85 F e ,83 Sit |AJ] 3CI^4S^ 2,3,14.5,61 4 4 101,07 2 7 58,93 C o 18. Cotian [Ar| 3d'4s^ 2,(31.141 4 5 102.91 H n 2.28 2 8 58,71 N i 181 Niken lAr) 3d*4s^ 2.131,141 4 6 106,40 H o 2.20 2 9 63,54 C u 190 Dong (Afl3d'V 1,2 4 7 107,87 A g 93 30 65,41 Z n 165 Kem [Ar] 3d'V 2 4 8 112.41 C d 168 3 1 69.72 Ga m Gall [Ati3(l'V4p' 3 4 9 114,82 I n 1,78 3 2 72,64 G e 201 Qemani [ArI3a"'4sV 2,4 5 0 118.69 S n 1S6 33 74.92 A s 2,18 Asen EATi3cl"'4sV -3,3,5 5 1 121,75 O D £.05 34 78,96 S © 2,55 Selen iAt33d'°4sV -2.4,6 5 2 127,60 T e 21 3 5 79,91 B r 2,86 Brom [At|3d^V4p^ •1.1,131.141.5,7 5 3 126.90 1 2,66 3 6 83.80 I x f 3fl Kripton tAfl3d'% V 2,4 5 4 131,30 X G 2.6 5 RU 2 2 Bac Cadlml Ttiife AnlirRon iStlbil Telu Xanon Rubhn l»15s' Strontl iKrlSs^ Ytri lKrl4d'5s^ Ziricani [Krl it^Ss^ NIobi iKr)4d*5s' Molipden |Kr]4(^5s' Tecnexi iKr)4d^5s^ RulenJ (Kf| 4()'5s' Rodi IKr) 4d^5s' Paladi (Krj4d'V IKr] 4d"'5s' [Krl4(l'V Indi il&34fl"'5s^5p' lK^4a'V^' [Krl4(l^V5p^ •3.3.(41.5 ^^12|^ , (Ktl4(f'V5p^ •1,1,3,5,7 [Kfl4d'V5p* 3,4,6 6 1 5 5 132,91 w S 0.79 XssI 1 2 5 6 137,31 D 3 0,B9 Bart 2 3 5 7 ' 138,91 L a 11 Lanlan 3 [21,131,4 7 2 178,49 Hf ,3 Hallnl |Xe|4f'V6s^ (21,131.4 |2].131.(41J 7 3 180,95 T a IS Tan Ian IXe)4i'V6s^ 121.131,141,5 2,3,4.161,6 7 4 183.85 W « Vonfam (Xel4('V6s^ 2,|3|,W,I51.6 3,4,151.161.7 7 5 186,20 R e ,9 Reni (Xel4l^*5{J^6s^ 12t,3,4,|5l,!6!.7 2,3,4,151,161,B 7 6 190,20 O S 22 Osimi [Xe|4("5(l*6s^ 2,3,4,161,8 2,3,4 7 7 192,20 l r 2,20 Iric^ lXel4f"5dV 2,3,4,161 2,131.4 7 8 195,09 r t 2,28 Platin [Xe|4f'V6s' 2,131.4,161 1,121 7 9 196,97 A U 254 VJing [XeHf'Vss' 1,3 2 8 0 200,59 r l Q 2,00 Ttiuy ngan !Xe|4l'^5d"'6s^ 1,2 1,3 8 1 204.37 T l ,62 Tall IXB^"5d"WV 1,3 2,4 8 2 207,20 H D 2,33 CM 2,4 8 3 208,98 D l 2,02 aitmut (Xel4l%"'6sV 3,5 84 [2091 85 12101 PO 20 A t 22 Poloni Atalin |Xel4l"5d"'asV Xel4i'*sa"^V -2,2,4,6 •1.1,3,5.7 8 6 (222) Rn Radon [Xe)4f'*5d^''aaV 141 7 87 I2S3I F r 0,7 Franid IBnlJt' 8 8 226,03 R 3 0,9 Radl 8 9 " 1227) A c 1, Acflni iRn) 6d'7s^ 104 105 106 107 108 109 110 Kim loai -<—^ ^— • Phi kim D Cac nguyen td s H Cac nguydn to p D Cac nguyen to d D Cac nguyen to f Ki hifiu ho^ tipc 1 2 3 * Hg Lantan ** Ho Actini 5 8 140.12 C e 112 Xen |Xe]4(^5d''6s^ 3,4 9 0 232,04 Tti ,3 Thort [Rn]5f"6d^7s^ 4 5 9 140,91 P r 1,13 Prazeodim [XeMrVss^ 3,4 9 1 231,04 P a 1. Protactini [Rn]5f^'7s^ 4,5 6 0 144,24 Nd ,» NeoiJi m [Xe]4f*5d°6s' 121,3,4 9 2 238,03 U t.38 Urani |Rr^5(^'7s^ 131,4.(51.6 61 [1471 P m 113 Prameti lx»141>5(f6s' 3 9 3 12371 N p 136 Neptuni lRt^5(*6d'7s^ (31,4,5,6 6 2 150,35 S m 117 Samari [XeMf^sa'es^ 2,3 9 4 [244] PU .28 Pluloni IRnlsl'tAs' 131,1,5,6 6 3 151,96 E u 1^ EuropI lX«Hl's H+ + e phai tieu tdn mot nang lucmg bang 1312 kJ/mol. Nang lucmg ion hoa thu" 2, thir 3 dugc kf hieu la Ij, I3 la nang lugng can de tach electron thii 2, 3 ra khdi cac ion tuong ung. Gia tri ciia chiing Idn hon nang lugng ion hoa thii nhat. Gia tri nang lugng ion hoa thii nha't ciia nguyen tir cac nguyen td nhdm A dugc trinh bay tren bang 2.2. Su bien ddi nang lugng ion hoa theo Z dugc bieu didn tren hinh 2.2. Bang 2.2 Nang iupng ion hoa thur nhat (kJ/mol) cua nguyen ttr cac nguyen to nhom A \ . Nhdm Chu ki\ ^ 1 2 3 4 5 6 IA H 1312 Li 520 Na 497 K 419 LRb 403 376 IIA Be 899 Mg 738 Ca 590 549 503 IIIA B 801 Al. 578 Ga 579 558 Tl 589 IVA 1086 Si 786 Ge 762 709 716 VA 1402 p 1012 As 947 834 703 VIA 0 1314 S 1000 Se 941 Te 869 812 VIIA F 1681 Cl 1251 Br 1008 1 1140 920 VIIIA He 2372 Ne 2081 Ar 1521 Kr 1351 Xe 1170 Rn 1037 Tii bang 2.2 va hinh 2.2 cho tha'y : Trong mgt chu ki, theo chiSu tang cua dien tfch hat nhan, luc lien ket giira hat nhan va electron ldp ngoai ciing tang, lam cho nang lugng ion hoa ndi chung ciing tang theo. 46 Trong cung mdt nhdm A, theo chieu tang ciia dien tich hat nhan, khoang each giira electron ldp ngoai cimg den hat nhan tang, luc lien ket giiia electron ldp ngoai cimg va hat nhan giam, do dd nang lugng ion hoa ndi chung giam. Thi du : Nang lugng ion hoa ciia liti (Li) bang 520 kJ/mol, cdn cua xesi (Cs) bang 376 kJ/mol. Xesi la nguyen to cd nang lugng ion hoa thap nha't (khdng ke franxi la nguyen td phdng xa), dl mat mdt electron trd thanh ion duong Cs+, nen xesi dugc dung trong te bao quang dien. L(kJ/mol) 1 2 3 4 5 -I—I—I—I—I—I—I—I—I—I—I—I—I—I—r 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Hinh 2.2. Subien doi gia tri cua 1, theo Z Vay : Ndng lugng ion hod thic nhdt cua nguyin tic cdc nguyen td trong bdng tudn hodn bie'n ddi tudn hodn theo chieu tdng cua diin tich hat nhdn. Ill - DO AM DIEN Do dm diin cua mgt nguyin tuddc trUng cho khd ndng hut electron cua nguyin tu dd khi tqo thdnh liin kit hod hgc. Nhu vay, do am dien cua nguyen tir nguyen td cang ldn thi tinh phi kim cua nguyen to dd cang manh. Ngugc lai, do am dien ciia nguyen tir nguyen td cang nhd thi tinh kim loai ciia nguyen to dd cang manh. Trong hoa hgc, cd nhilu thang do am dien khac nhau do cac tac gia tfnh toan dua tren nhung co sd khac nhau. Dudi day gidi thieu bang gia tri do am dien cua nha hoa hgc Pau-linh (L.Pauling) thiet lap nam 1932. Vi nguyen td flo la phi kim manh nhat, Pau-linh quy udc lay do am dien cua flo de xac dinh do am dien tuong dd'i cua nguyen tir cac nguyen td khac. 47 Bang 2.3 Gia tri do am dien cua nguyen tir mot so nguyen to nhom A theo Pau-linh ^ \ Nhom Chu ki\ . 1 2 3 4 5 6 IA H 2,20 Li 0,98 Na 0,93 K 0,82 Rb 0,82 Cs 0,79 IIA Be 1,57 Mg 1,31 Ca 1,00 Sr 0,95 Ba 0,89 IIIA B 2,04 Al 1,61 Ga 1,81 In 1,78 Tl 1,62 IVA C 2,55 Si 1,90 Ge 2,01 Sn 1,96 Pb 2,33 VA N 3,04 P 2,19 As 2,18 Sb 2,05 Bi 2,02 VIA O 3,44 S 2,58 Se 2,55 Te 2,10 Po 2,00 VIIA F 3,98 Cl 3,16 Br 2,96 I 2,66 At 2,20 Su bie'n ddi dd am dien theo Z duoc bieu diln tren hinh 2.3. 4 - E 2 •o O 1- —I r 5 T 1 1 10 15 20 Hinh 2.3. Subien doi dd am dien theo Z Txt bang 2.3 va hinh 2.3 cho tha'y su bie'n ddi do am dien cua nguyen tir cac nguyen td nhu sau : 48 Trong mot chu ki, theo chiiu tang dan ciia dien tfch hat nhan, do am dien cua nguyen tir cac nguyen td thudng tang dan. Trong ciing mot nhdm A, theo chiiu tang ciia dien tich hat nhan, do am dien cua nguyen tir cac nguyen td thudng giam dan. Vay : Do dm diin cua nguyin tic cdc nguyin td trong bdng tudn hodn biin doi tudn hodn theo chieu tdng cua diin tich hat nhdn. BAI TAP 1. Trong mot chu ki, ban kfnh nguyen tiT cac nguyen td A. tang theo chieu tSng cua dien tfch hat nhan. B. giam theo chieu tang cCia dien tfch hat nhan. C. giam theo chieu t§ng cua dp am dien. D. Ca B va C Chpn dap an dung nhat. 2. Trong mot nhdm A, ban kfnh nguyen tCr cua cac nguyen td A. tang theo chieu tang cua dien tfch hat nhan. B. giam theo chieu tang cua dien tfch hat nhan. C. tang theo chieu giam cua do am dien. D. Ca A va C Chpn dap an dung nhat. 3. Dp am dien dac trUng cho kha nang A. hut electron cua nguyen tCf trong phan tCr. B. nhudng electron cua nguyen td nay cho nguyen tCr khac. C. tham gia phan irng manh hay yeu. D. nhudng proton cua nguyen tCr nay cho nguyen tCf khac. Chpn dap an diing. 4. Hay cho bie't sU bien ddi nang lupng ion hoa thir nhat cua nguyen td cac nguyen td trong cung mot chu ki va trong ciing mot nhdm A. 5. Neu khdng xet khf hiem thi nSng lupng ion hoa thir nhat cua nguyen tir nguyen td nao Idn nhat, cua nguyen tCr nguyen td nao nhd nhat ? 6. Dp am dien cua mot nguyen td la gi ? Quy luat bien ddi gia trj dp am dien cua nguyen tCr cac nguyen td trong cac nhdm A nhU the nao ? 7. Nguyen td cua nguyen td nao cd gia trj dp am dien Idn nhat ? 49 4 - HN10/NC-A ^ ^ liai (to^ thiitL. Al LUC ELECTRON Ai lire electron ciia nguyen tu la nang lugng tea ra hay hap thu khi mot nguyen td trung hoa d trang thai khi nhan mot electron de trd thanh mot ion mang dien ti'ch 1 - cung nam d trang thai dd. Nhu vay, ai luc electron la hieu irng nang lugng CLia qua trinh : A (khf) + e ^ A- (khf) Ai luc electron ciia mdt moi nguyen tu dugc tfnh bang kJ/mol. Ngudi ta quy udc dat da'u - cho ai luc electron khi cd su toa ra nang lugng va da'u + khi cd su hap thu nang lugng tu ben ngoai. Phan Idn cac nguyen td hoa hgc cd ai luc electron am, nhung cac nguyen to nhdm IIA, IIB va cac khf tra cd ai luc electron duang. Quy luat bien thien ai luc electron theo chieu tang ciia dien tich hat nhan nguyen tu ciia cac nguyen to hoa hgc khdng that ro ret va nhat quan nhu cac quy luat tim tha'y dd'i vdi do am dien va nang lugng ion hoa. Tuy nhien, cung cd the rut ra mdt sd nhan xet sau day : - Nhin chung, cac phi kim cd ai luc electron mang dau am vdi gia trj tuyet ddi Idn han kim loai. Cac halogen cd ai luc electron am vdi gia trj tuyet dd'i Idn hon d cac nguyen td khac ciia bang tuan hoan, vi nhdm nguyen to nay dd thu them electron. Khf hiem cd Idp electron ngoai cung bao hoa (hoac gia bao hoa), chung khd thu them electron nen cd ai luc electron duang. - Trong phan Idn trudng hgp, trong mgt nhdm A, theo chieu tang cua dien tich hat nhan ai luc electron am cd gia tri tuyet dd'i giam dan. - Trong mgt chu ki, nhin chung gia tri tuyet dd'i ciia ai luc electron am tang dan theo chieu tang cua dien tfch hat nhan. Nhung cac khf hiem lai cd ai luc electron duang. Vi giOa do am dien va ai luc electron phai cd mdi lien quan chat che vdi nhau, Muliken (Mulliken scale) da su dung cac gia tri ai luc electron va nang lugng ion hoa de xay dung thang do am dien mang ten ong. Dieu dang chii y la, trong khi khai niem do am dien thudng diing cho cac nguyen tu, thi ai luc electron cdn dugc ap dung cho ca cac phan tu. ChSng han, ngudi ta dua ra gia tri ai luc electron duang cho benzen, antraxen, gan bang khdng cho phan tu naphtalen. Vi the, ai luc electron dugc dung de giai thfch kha nang phan ung ciia nhieu chat huu ca. 50 4 - HN10/NC-B ^di IZ15 SU " BIEN DOI TINH KIM LOAI TINH PHI KIM CUA CAC NGUYEN TO HOA HOC DINH LUAT TUAN HOAN • Hieu dircrc tinh kim loai, tinh phi kim va quy luat bie'n doi tinh kim loai, tinh phi kim cua cac nguyen to trong bang tuan hoan. • Hieu duoc quy luat bien doi hoa trj, tinh axit - bazd cua oxit va hidroxit cua cac nguyen to trong bang tuan hoan. • Hieu diTdc noi dung djnh luat tuan hoan. I - Si; BIEN DOI TiNH KIM LOAI, TINH PHI KIM CUA CAC NGUYEN TO 1. Tinh kim loai, tinh phi kim Tinh kim loai la tinh chdt cua mdt nguyin td md nguyin tic cua nd di nhudng electron de tra thdnh ion duang. Nguyen tir cua nguyen td nao cang dl nhudng electron, tfnh kim loai ciia nguyen td dd cang manh. Tinh phi kim la tinh chdt ciia mdt nguyin tdmd nguyen tic cua nd di nhdn thim electron de tra thdnh ion dm. Nguyen tir ciia nguyen td nao cang dl nhan electron, tfnh phi kim ciia nguyen td dd cang manh. Thuc ra, khdng cd ranh gidi rd ret giiia tfnh kim loai va tfnh phi kim. Mgt each tuong dd'i, trong bang tuan hoan cac nguyen td kim loai va phi kim dugc phan each bang dudng ke dam (xem bang tuan hoan trang 41). Ben phai la cac nguyen td phi kim, ben trai la cac nguyen td kim loai. 2. Sir bien doi tinh kim loai, tinh phi kim Trong mdi chu ki, theo chiiu tdng cua diin tich hat nhdn, tinh kim loai ciia cdc nguyin td gidm ddn, ddng thdi tinh phi kim tdng ddn. Thi du : Chu ki 3 bat dau tir nguyen td natri (Z = 11), mdt kim loai dien hinh, rdi lan lugt den magie (Z = 12) la kim loai manh nhung hoat ddng kem natri. Nhdm (Z = 13) la kim loai nhung hidroxit ciia nd da cd tinh ludng tinh. 51 Silic (Z = 14) la phi kim. Tir photpho (Z = 15) den luu huynh (Z = 16), tfnh phi kim manh dan, clo (Z = 17) la mdt phi kim dien hinh. Quy luat tren dugc lap lai dd'i vdi mdi chu ki. Cd the giai thich quy luat bien ddi tfnh chat tren nhu sau : Trong mdt chu ki, theo chiiu tang ciia dien tfch hat nhan (tir trai sang phai) thi nang lugng ion hoa, do am dien tang din ddng thdi ban kfnh nguyen tir giam dan lam cho kha nang nhudng electron giam nen tfnh kim loai giam, kha nang nhan electron tang nen tfnh phi kim tang. Trong mot nhdm A, theo chiiu tdng cua diin tich hat nhdn tinh kim loai cua cdc nguyin td tdng ddn, ddng thdi tinh phi kim gidm ddn. Thf du nhdm IA va nhdm VIIA. Trong nhdm IA : Tinh kim loai tang rd ret tir liti (Z = 3) den xesi (Z - 55) tiic la kha nang nhudng electron tang dan. Nhdm VIIA (nhdm halogen) gdm nhiing phi kim dien hinh : Tfnh phi kim giam din tii flo (Z = 9) ddn iot (Z = 53), tiic la kha nang nhan electron giam dan. Quy luat dd dugc lap lai dd'i vdi cac nhdm A khac va dugc giai thfch nhu sau : Trong mdt nhdm A, theo chiiu tang cua dien tfch hat nhan (tir tren xud'ng dirdi) thi nang lugng ion hoa, do am dien giam dan ddng thdi ban kfnh nguyen tir tang nhanh lam cho kha nang nhudng electron tang, nen tfnh kim loai tang, kha nang nhan electron giam, nen tfnh phi kim giam. Tinh kim loai, tfnh phi kim cua cac nguyen to phu thudc chu ydu vao cau hinh electron nguyen tir. Cau hinh electron nguyen tir cua cac nguyen to trong bang tuan hoan cd tinh bie'n ddi tuan hoan nen tfnh kim loai, tfnh phi kim biln doi tuan hoan. Nhan xet: Tinh kim loai, tinh phi kim cua cdc nguyin td trong bdng tudn hodn biin ddi tudn hodn theo chieu tdng cua diin tich hat nhdn. II - SU BIEN DOI VE HOA TRI CUA CAC NGUYEN T 6 Trong mdt chu ki, di tir trai sang phai, hoa tri cao nhat cua cac nguyen td vdi oxi tang lan lugt tii 1 den 7, cdn hoa tri vdi hidro cua cac phi kim giam tir 4 den 1. 52 Thi du : Trong chu ki 3, ba nguyen td dau chu ki (Na, Mg, Al) tao thanh hgp chat oxit trong dd cac nguy6n td cd hoa tri lan lugt la 1, 2, 3. Cac nguyen td tiep theo (Si, P, S, Cl) cd hoa tri lan lugt la 4, 5, 6, 7 trong oxit cao nhat. Cac nguyen td phi kim Si, P, S, Cl tao dugc hgp chat khf vdi hidro, trong dd chiing cd hoa tri lan lugt la 4, 3, 2, 1. Dd'i vdi cac chu ki khac, su bien ddi hoa tri ciia cac nguyen td ciing diln ra tuong tu (bang 2.4). Bang 2.4 Sir bien doi tuan hoan hoa trj cua cac nguyen to 6 chu ki 3 va 4 So thur tir nhom A Hgp chat vdi oxi Hoa trj cao nha't vdi oxi Hop chat khf vdi hidro Hoa tri vdi hidro IA Na20 K2O 1 IIA MgO CaO 2 IIIA AI2O3 Ga203 3 IVA Si02 Ge02 4 SiH4 GeH4 4 VA P2O5 AS2O5 5 PH3 ASH3 3 VIA SO3 Se03 6 H2S H2Se 2 VIIA CI2O7 Br207 7 HCI HBr 1 Nhan xet : Hod tri cao nhdt cua mdt nguyin td vdi oxi, hod tri vdi hidro ciia cdc phi kim biin ddi tudn hodn theo chieu tdng ciia diin tich hat nhdn. I - SU BIEN DOI TINH AXrr - BAZO CUA OXIT VA HIDROXIT TUONG UNG Tfnh axit - bazo ciia oxit va hidroxit tuong ling cua cac nguyen td d chu ki 2 va 3 dugc trinh bay trong bang 2.5. 53 Bang 2.5 Tinh axit - bazo cua oxit va hidroxit tuong ung cua cac nguyen to 6 chu ki 2 va 3 Li20 BeO : B2O3 j 1 Oxit bazo , ,-, ,, , Oxit axit j luong tmh 1 CO2 Oxit axit N2O5 Oxit axit LiOH Be(0H)2 H3BO3 H2CO3 1 HNO3 ,.., t Hidroxit ' ^ .^ ., ! Bazo kiem , _ , , Axit yeu luong tmh Axit yeu Axit manh Na20 MgO Oxit bazo Oxit bazo 1 ,1 ! AI2O3 ' Oxit ludng tinh L ..- . J Si02 Oxit axit P2O5 Oxit axit SO3 Oxit axit J CI2O7 Oxit axit NaOH Mg(0H)2 ! AI(0H)3 H2Si03 H3PO4 ; H2SO4 1 HCIO4 ...-' „ ,. ! Hidroxit I . ., ., ! Bazo kiem Bazo yeu , _ , . 1 Axit yeu luong tinh , , . Axit manh trung binh: Axit rat manh Trong mdt chu ki, theo chiiu tang cua dien tfch hat nhan, tinh bazo ciia oxit va hidroxit tuong ling giam ddn, ddng thdi tfnh axit cua chiing tang dfo. Trong mot nhdm A, theo chiiu tang cua dien tfch hat nhan, tfnh bazo cua cac oxit va hidroxit tuong ling tang dSn, ddng thdi tfnh axit ciia chiing giam din. Nhan xet: Tinh axit - baza cua cdc oxit vd hidroxit tuang icng cua cdc nguyen tdbii'n ddi tudn hodn theo chieu tdng ciia diin tich hat nhdn nguyin tic. IV - DINH LUAT TUAN HOAN Dinh luat tudn hoan dugc phat bieu nhu sau : "Tinh chdt cua cdc nguyin tdvd dan chdt ciing nhu thdnh phdn vd tinh chdt cua cdc hgp chd't tqo nin tit cdc nguyin td dd biin doi tudn hodn theo chieu tang cua dien tich hat nhdn nguyen tic". 54 BAI TAP 1. Cho biet quy luat bien ddi tfnh kim loai, tinh phi kim cCia cac nguyen td trong mdt chu ki va trong mot nhdm A, giai thich. 2. Hay cho biet sU bien ddi ve tfnh axit - bazd cua cac oxit cao nhat va hidroxit tuong umg cija cac nguyen td trong mot chu ki va trong mot nhdm A theo chieu tang cua dien tfch hat nhan. 3. Hay phat bieu djnh luat tuan hoan cac nguyen to hoa hpc va lay cac thf du ve cau hinh electron nguyen tCr, tfnh chat cCia cac ddn chat va tfnh chat cua cac hop chat de minh hoa. 4. Nhufng dai lUdng va tinh chat nao cua nguyen td hoa hoc (ghi dudi day) bien ddi tuan hoan theo chieu tang dien tfch hat nhan nguyen td ? a) Khdi lupng nguyen td b) Sd thir tu c) Ban kfnh nguyen td d) Tfnh kim loai e) Tinh phi kim f) NSng lugng ion hoa thir nhat i) Tfnh axit - bazd cua cac hidroxit k) Cau hinh electron nguyen tir Idp ngoai cung. 5. Cho cac nguyen td X, Y, Z cd sd hieu nguyen tCr lan lugt la 9, 16, 17. a) Xac djnh vi tri cua chung trong bang tuan hoan. b) Xep cac nguyen td dd theo thir tu tfnh phi kim tang dan. 6. Cho cac nguyen toA, B, C, D cd sd hieu nguyen tir lan lUdt 11, 12, 13, 14. a) Viet cau hinh electron nguyen tCrcua chiing. b) Xac djnh vj trf cua chiing trong bang tuan hoan. c) Xep cac nguyen td do theo thir tU tfnh kim loai tang dan. 7. Dua vao sU bien ddi tuan hoan tfnh chat ciia cac nguyen td, hay doan nhan sU bie'n ddi ve nang lUOng ion hoa thir nhat, dp am dien, tfnh kim loai cua cac kim loai nhdm IA. 55 m 13 Y NGHiA CUA BANG TUAN HOAN CAC NGUYEN T 6 HOA HOC • Vj tri cua mot nguyen to hoa hoc trong bang tuan hoan cho ta nhCimg thong tin gi ve nguyen to do. • Khi biet so hieu nguyen tur cua mot nguyen to, ta co the suy ra vj tri cua no trong bang tuan hoan diroc khong ? I - QUAN HE GILTA Vj TRI VA CAU TAO NGUYEN TU Bii't vi tri cua mgt nguyin td trong bdng tudn hodn, cd the suy ra cdu tqo nguyen tic cua nguyin td do vd ngugc lai (xem sa dd sau) : Vi tri cua mgt nguyen td Cdu tqo nguyen tii trong bdng tudn hodn (d) - Sd thii tu cua nguydn td < > - Sd proton, sd electron - Sd thii tu cua chu ki - Sd ldp electron - Sd thii tii cua nhdm A - Sd electron ldp ngoai ciing Thi du 1 : Biet nguySn td cd sd thii tu la 19 thudc chu ki 4, nhdm IA, cd thi suy ra: • Nguyen tir ciia nguyen td dd cd 19 proton, 19 electron, cd 4 ldp electron (vi sd ldp electron bang sd thii tu cua chu ki), cd 1 electron d ldp ngoai cung (vi sd electron ldp ngoai ciing bang sd thii tu ciia nhdm A). Dd la nguydn td kali. Thi du 2 : Bie't cau hinh electron nguyen tit cua mdt nguyen td la Is^ 2s2 2p6 3s2 3p* cd the suy ra : Tdng sd electron cua nguyen tir nguyen td dd la 16, vay nguyen td dd chiem 6 thii 16 trong bang tudn hoan (vi nguyen tir cd 16 electron, 16 proton, sd don vi dien tfch hat nhan la 16 bang sd thii tu cua nguyen to trong bang tudn hoan). Nguyen td dd thudc chu ki 3 (vi cd 3 ldp electron), nhdm VIA (vi cd 6 electron ldp ngoai ciing). Dd la nguyen td luu huynh. II - QUAN HE GIQA Vj TRI VA TINH CHAT CUA NGUYEN TO Bii't vi tri cua mgt nguyin td trong bdng tudn hodn, cd the suy ra nhiing tinh chdt hod hgc ca bdn cua nd. 56 - Tinh kim loai, tfnh phi kim : Cac nguyen td d cac nhdm IA, IIA, IIIA (trir hidro va bo) cd tfnh kim loai. Cac nguyen td d cac nhdm VA, VIA, VIIA cd tfnh phi kim (trir antimon, bitmut va poloni). - Hoa tri cao nhdt ciia nguyen td vdi oxi, hoa tri vdi hidro. - Cdng thiic cua oxit cao nhat va hidroxit tuong ung. - Cdng thiic cua hgp chat khf vdi hidro (neu cd). - Oxit va hidroxit cd tfnh axit hay baza. Thi du : Nguyen td luu huynh d d thii 16, nhdm VIA, chu ki 3. Suy ra luu huynh la phi kim. Hoa tri cao nhdt vdi oxi la 6, cdng thii-c cua oxit cao nha't la SO3. Hoa tri vdi hidro la 2, cdng thiic ciia hgp chdt khf vdi hidro la H2S. SO3 la oxit axit va H2SO4 la axit manh. I - SO SANH TINH CHAT HOA HQC CUA MO T NGUYEN TO VOI CAC NGUYEN TO LAN CAN Dua vao quy luat bien ddi tfnh chat ciia cac nguyen td trong bang tudn hoan cd thi so sanh tfnh chdt hoa hgc cua mdt nguyen td vdi cac nguyen td lan can. Thi du : So sanh tinh chat hoa hoc ciia P (Z = 15) vdi Si (Z = 14) va S (Z = 16), vdi N (Z = 7) va As (Z = 33). Trong bang tudn hoan, cac nguyen td Si, P, S thudc ciing mdt chu ki. Neu xep theo thii tu dien tfch hat nhan tang ddn ta dugc day Si, P, S. Trong chu ki, theo chiiu dien tfch hat nhan tang thi tfnh phi kim tang. Vay P cd tfnh phi kim yeu hon S va manh hon Si. Trong nhdm VA, theo chiiu dien tfch hat nhan tang ddn, tfnh phi kim giam dan. Vi vay theo thii tu N, P, As, thi P cd tinh phi kim yeu hon N va manh hon As. Vay P cd tfnh phi kim yeu hon N va S, hidroxit cua nd la H3PO4 cd tinh axit yeu hon HNO3 va H2SO4. BAI TAP 1. Theo quy luat bie'n ddi tfnh chat cua cac nguyen td trong bang tuan hoan thi A. phi kim manh nha't la iot. B. kim loai manh nhat la liti. C. phi kim manh nhat la flo. D. kim loai yeu nha't la xesi. Chpn dap an dimg. 57 2. Cho nguyen td X (Z = 12), hay cho biet: - Cau hinh electron nguyen tir cua nguyen td X. - Tinh chat hoa hpc cd ban ciia nguyen td X. 3. Dua vao quy luat bien ddi tfnh kim loai, tfnh phi kim ciia cac nguyen td trong bang tuan hoan, hay neu : a) Nguyen td nao la kim loai manh nhat ? Nguyen td nao la phi kim manh nha't ? b) Cac nguyen td kim loai dUdc phan bd d khu vUc nao trong bang tuan hoan ? c) Cac nguyen td phi kim dUOc phan bd d khu vUc nao trong bang tuan hoan ? d) Nhdm nao gdm nhtirig nguyen td kim loai dien hinh ? Nhdm nao gdm nhufng nguyen td phi kim dien hinh ? e) Cac nguyen td khf hiem nam d khu vUc nao trong bang tuan hoan ? 4. Nguyen tir ciia 2 nguyen td cd Z = 25 va Z = 35. a) Xac djnh sd thd tU chu ki va nhdm cua cac nguyen td tren trong bang tuan hoan. b) Neu tinh chat hoa hgc cd ban ciia hai nguyen td dd. 5. Nguyen td X cd sd hieu nguyen tir la 16. - Viet cau hinh electron nguyen tir ciia nguyen td X. - Cho biet tfnh chat hoa hpc cd ban ciia nguyen td X. 6. Bang dudi day cho biet ban kinh nguyen tir va nang lUOng ion hoa thir nhat cua nguyen tCr mot sd nguyen td Nguyen to Ban kfnh nguyen tCr (nm) NSng lugng ion hoa thir nhat (kJ/mol) Na 0,157 497 Mg 0,136 738 Al 0,125 578 Si 0,117 786 P 0,110 1012 s 0,104 1000 Cl 0,099 1251 Dua vao cac dd kien tren, hay rut ra nhdng nhan xet sau : a) Su bien ddi ban kinh nguyen tir ciia cac nguyen td trong chu ki. b) Su bien ddi nang lugng ion hoa I-| cua nguyen tu" cac nguyen td trong chu ki. 7. Phat bieu djnh luat tuan hoan va cho biet nguyen nhan ciia sU bien ddi tuan hoan tfnh kim loai, tfnh phi kim ciia cac nguyen td theo chieu tang cua dien tich hat nhan nguyen tir. 8. Nguyen td clo thudc chu ki 3 va nhdm VIIA, hay cho biet dac diem ve cau hinh electron nguyen tCr va tfnh chat hoa hoc cd ban ciia clo. 9. Nguyen td natri thudc chu ki 3 va nhdm IA, hay cho biet dSc diem ve cau hinh electron nguyen tir va tinh chat hoa hgc cd ban cua natri. 10. Hay so sanh tfnh kim loai ciia Mg (Z = 12) vdi Na (Z = 11) va Al (Z = 13). 58 (Bdi 14 LUYEN TAP CHUONG 2 • Cung CO cac kien thiirc : - Cau tao bang tuan hoan cac nguyen to hoa hoc. - Quy luat bien doi tuan hoan mot so dai luang vat li va tinh chat cac nguyen to theo chieu tang cCia dien tich hat nhan. - Dinh luat tuan hoan. • Ren luyen kT nang : Lam cac bai tap xac lap moi quan he giCfa vi tri, cau tao nguyen tCf cac nguyen to va tinh chat cCia nguyen to. A - KIEN THLfC CAN NAM VQN G 1. Nguyen tac sap xep cac nguyen to trong bang tuan hoan 2. Cau tao bang tuan hoan cac nguyen to hoa hor - O : Sd thii tu cua d bang sd hieu nguyen tir, bang sd don vi dien tfch hat nhan va bang tdng sd electron. - Chu ki : Sd thii tu cua chu ki bang sd ldp electron. + Chu ki nhd la cac chu ki 1, 2, 3 chi gdm cac nguyen td s va nguyen td p. + Chu ki ldn la cac chu ki 4, 5, 6, 7 gdm cac nguyen td s, p, d va f. - Nhdm : Sd thii tu ciia nhdm bang sd electron hoa tri. + Nhdm A : Sd thii tu cua nhdm A bang sd electron ldp ngoai cung. Nhdm A gdm cac nguyen td s va p. + Nhdm B : Sd thii tu ciia nhdm B bang sd electron hoa tri. Nhdm B gdm cac nguyen td d va f. 3. Nhung dai lupng va tinh chat bien doi tuan hoan theo chieu tang ciia dien tich hat nhan - Ban kfnh nguyen tir. - Nang lugng ion hoa thii nhdt. 59 - Do dm dien. - Tfnh kim loai, tfnh phi kim. - Tfnh axit - bazo cua oxit va hidroxit. - Hoa tri cao nhdt ciia nguyen td vdi oxi va hoa tri ciia nguyen td phi kim vdi hidro. 4. Dinh luat tuan hoan "Tinh chd't cua cdc nguyin tdvd dem chdt cUng nhu thdnh phdn vd tinh chdt ciicdc hgp chdt tqo nin tic cdc nguyin td dd bie'n doi tudn hodn theo chieu tdng cua diin tich hqt nhdn nguyin t^". B - CAU HOI VA BAI TAP 1. NhOmg cau sau day, cau nao sai ? A. Trong chu ki, cac nguyen td dUOc xep theo chieu dien tfch hat nhan tang dan. B. Trong chu ki, cac nguyen td dugc xep theo chieu sd hieu nguyen tir tang dan. C. Nguyen tir ciia cac nguyen td cimg chu ki cd sd electron bang nhau. D. Chu ki bao gid cung bat dau la mot kim loai kiem, cud'i cung la mdt khi hiem (trd chu ki 1). 2. a) Dua tren nguyen tac nao ngudi ta xep cac nguyen td thanh chu ki, nhdm ? b) The nao la chu ki ? Bang tuan hoan cd bao nhieu chu ki nhd, bao nhieu chu ki Idn ? Mdi chu ki cd bao nhieu nguyen td ? 3. Trong bang tuan hoan, nhdm A nao gdm tat ca cac nguyen td la kim loai ? Nhdm nao gdm hau het cac nguyen td la phi kim ? Nhdm nao gdm cac nguyen td khf hiem ? DSc diem sd electron Idp ngoai cimg ciia cac nguyen tCr trong cac nhdm tren. 4. Tdng sd hat proton, ndtron, electron cua nguyen tif mdt nguyen td thudc nhdm VIIA la 28. a) Tinh nguyen tir khdi. b) Viet cau hinh electron nguyen tir cua nguyen td dd. 5. Oxit cao nhat ciia mdt nguyen td la RO3, trong hgp chat ciia nd vdi hidro cd 5,88% hidro ve khdi lUdng. Xac djnh nguyen to dd. 6. Hdp chat khi vdi hidro cua mdt nguyen td la RH4. Oxit cao nhat ciia nd chira 53,3% oxi ve khdi lugng. Tim nguyen td dd. 60 7. Khi cho 0,6 g mot kim loai nhdm IIA tac dung het vdi nUdc tao ra 0,336 Ift khf hidro (6 dieu kien tieu chuan). Xac djnh kim loai dd. 8. Hai nguyen td A, B dimg ke tiep nhau trong cung mot chu ki cua bang tuan hoan c6 tdng sd ddn vj dien tich hat nhan la 25. a) Viet cau hinh electron de xac djnh hai nguyen td A va B thudc chu ki nao, nhom nao. b) So sanh tinh chat hoa hpc ciia chiing. 9. Cho 8,8 g mot hon hdp hai kim loai nam d hai chu ki lien tiep nhau va thudc nhdm IIIA, tac dung vdi HCI duthi thu dUdc 6,72 Ift khf hidro d dieu kien tieu chuan. Dua vao bang tuan hoan cho bie't ten ciia hai kim loai dd. 10. Nguyen td X cd cau hinh electron nhU sau : Is^ 2s2 2p6 Ss^ 3p6 3d5 4s'' Hay xac djnh : a) Vi trf ciia X trong bang tuan hoan. b) Neu tfnh chat hoa hpc cd ban ciia X. 11. Viet cau hinh electron nguyen tir ciia cac nguyen td trong nhdm IA: Li, Na, K, Rb, Cs. Hay sap xep cac nguyen td dd theo chieu giam dan ciia ban kinh nguyen tir, giai thich. 61 (Bdi 15 BAI THirC HANH SO 1 MOT SO THAO TAC THlfC HANH THI NGHIEM HOA HOC. SU BIEN DOI TINH CHAT CUA CAC NGUYEN TO TRONG CHU Ki VA NHOM • Giup hoc sinh ren luyen mot so kT nang sur dung hoa chat va dung cu thi nghiem de dam bao an toan va ket qua thi nghiem. • Tien hanh mot so thi nghiem ddn gian ve sir bien doi tinh chat cua nguyen to trong chu ki va nhom. I -NOI DUNG 1. Mot so thao tac thirc hanh thi nghiem hoa hoc a) Lay hoa chat Khi md mit Ig lay hoa chat, phai dat ngira mit tren mat ban de dam bao do tinh khiet ciia hoa chat va tranh hoa chat day ra ban. Lay hoa chat ran phai dung thia xiic hoac kep, khdng cdm bang tay (hinh 2.4). Ldy hoa chat long phai dung dng hiit nhd gigt. Khi dd hoa chat tir Ig nay sang Ig khac phai dung ph6u. Khi rdt hoa chat vao dng nghiem phai dung cap giu dng nghiem, de tranh hoa chat day ra tay. b) Trdn cac hoa chait Hinh 2.4. Cach lay hoa chat rSn Khi trdn hoac hoa tan cac hoa chat trong cdc phai dung dua thuy tinh. 62 Trdn hoac hoa tan cac hoa chdt trong dng nghiem phai cdm mieng dng bang cac ngdn tay trd, cai va giiia ciia ban tay. De dng hoi nghieng va Idc bang each dap phdn dudi cua dng vao ngdn tay trd hoac Idng ban tay ben kia cho de'n khi chat long dugc trdn d6u. Khong dugc dung ngdn tay bit mieng dng nghiem va Idc, vi nhu vay se lam hoa chdt day ra tay. Neu lugng hoa chdt chiia qua — dng nghiem thi phai dung dua thuy tinh khuay nhe. c) Dun ndng hoa chat Khi dun hod chdt rdn trong dng nghiem cdn cap dng nghiem d tu the ndm ngang tren gia thf nghiem, mieng dng hoi chiic xud'ng de de phdng hoi nudc tii hod chdt thoat ra, dgng lai va chay ngugc xud'ng day dng nghiem dang ndng va lam vd dng. Dun hoa chat long trong cdc thuy tinh phai dung ludi (thep khdng gi hoac ddng) Idt dudi day cdc thuy tinh de tranh nut vd. Khdng dugc ciii mat gdn mieng cdc dang dun ndng de tranh hoa chdt sdi ban vao mdt va mat (hinh 2.5). d) Sii dung mgt sd dung cu thi nghiem thdng thudng Trong thf nghiem thuc hanh hoa hgc thudng diing cap gd hoac kim loai, cap d vi trf each mieng dng nghiem bang 1/3 chieu dai cua dng nghiem. Khi da cho dng nghiem vao cap rdi, chi nen ndm chdc nhanh dai ciia cap va dat ngdn tay cai len nhanh ngdn, khdng dimg ban tay ndm ca hai nhanh ciia cap. Hinh 2.5. Cach dun chat long trong coc thuy tinh Hinh 2.6. Cach cham lira den con 63 Khi cham den cdn phai dung que ddm. Khdng nghieng den cham lira tir den nay sang den khac de tranh cdn chay ra ngoai gay chay, bdng (hinh 2.6). Khi tat den cdn phai diing chup day, khdng thdi nggn lira bdng mieng. Khi dun chdt long trong cac dung cu thuy tinh nhu dng nghiem, a) b) Hinh 2.7. Cach xac dinh thS tich chat long a) doc sai; b) doc dung cdc,... nen dat chd cdn dun ndng cua cac dung cu vao didm ndng nhat cua ngon lira den cdn, d vi tri — chieu cao nggn lira tfnh tir tren xudng. Khi dgc muc chd't long trong cac dung cu dong, do chd't long, cdn d^ tdm mdt nhin ngang vdi day vdm khum cua chat long chiia trong cac dung cu (hinh 2.7). 2. Thirc hanh ve sif bien doi tinh chat cua nguyen to trong chu ki va nhom a) Sir bien ddi tinh chat ciia cac nguyen to trong nhdm Ldy vao hai cdc thuy tinh, mdi cdc chiing 60 ml nudc. Nhd vao mdi cdc vai giot dung dich phenolphtalein va khudy deu. Cho vao cdc thii nhdt mdt mau nhd natri, cdc thii hai mdt mau kali cd ciing kfch thudc (chii y bao dam an toan khi lam thf nghiem vdi kali). Quan sat hien tugng xay ra trong mdi cdc. Nhan xet va nit ra kdt ludn v6 sii biS'n ddi tfnh chdt ciia cac nguyen td trong nhdm. b) Su bien ddi tinh chat ciia cac nguyen td trong chu ki Rdt vao hai cdc thuy tinh, mdi cdc chiing 60 ml nudc. Rdt vao cdc thii ba chiing 60 ml nudc ndng. Nhd vao mdi cdc vai gigt dung dich phenolphtalein rdi khudy d6u. Cho vao cdc thii nhat mdt mdu nhd natri nhu da gidi thidu d thi nghiem (a). Cho vao cdc thii hai va cdc thii ba, mdi cdc mdt mdu magie cd kich thudc bang mdu natri. Quan sat hien tugng xay ra trong mdi cdc. Nhdn xet va nit ra kdt ludn v6 su bie'n ddi tfnh chat cua cac nguyen td trong chu ki. II - VIET TUONG TRINH 64 Chuang ^ LIEN KET HOA HOC y^ Tai sao trong tu nhien nguyen tCi' cac nguyen to' lai ton tai chD yeu dudi dang phan tii hoSc tinh the ? ^ The nao la mot lien ket hoa hoc ? C6 nhOfng kieu lien ket hoa hoc nao ? M6 hinh dSc ciia mot s6 phSn tif 5 • HN10/NC-A 65 (Bdi 16 KHAI NIEM V£ LI£N K ^ HOA HOC LIEN KET ION • Cac ion duoc tao thanh nhir the nao ? • The nao la cation va anion ? The nao la ion ddn, ion da nguyen tur ? • Lien ket ion diroc hinh thanh nhir the'nao ? • Cau tao mang tinh the ion va cac tinh chat chung cua mang lien quan vdi nhau nhirthe nao ? I - KHAI NIEM VE LIEN KET HOA HOC 1 . Khai niem ve lien ket Liin ki't hod hgc Id suki't hgp giita cdc nguyin tic tqo thdnh phdn tic hay tinh tben vicng han. Khi cd su chuyen cac nguyen tir rieng re thanh phan tir hay tinh the tiic la cd lien ket hod hgc thi nguyen tir cd xu hudng dat tdi cdu hinh electron bdn vung ciia khi hiem. Mdt each tdng quat, su lien ket giiia cac nguyen tir tao thanh phan tir hay tinh the dugc giai thfch bdng su gidm ndng lugng khi chuyen cac nguyen tit rieng re thanh phan tir hay tinh the. 2. Quy tac bat tir (8 electron) Ta da biet, cac khf hiem hoat ddng hod hgc rdt kem, chiing tdn tai trong tu nhien dudi dang nguyen tir tu do rieng re, nguyen tir cua chiing khdng lien ket vdi nhau tao thanh phan tir. Trong cac nguyen tir khf hiem, nguyen tir heli chi cd 2 electron nen cd 2 electron d ldp thii nhat ciing la ldp ngoai ciing, cdn cac nguyen tir khi hiem khdc 6tu co 8 electron d ldp ngoai ciing. Nhu vay, cdu hinh vdi 8 electron a lap ngodi ciing (hodc 2 electron ddi vdi heli) la cdu hinh electron viCng bin. Theo quy tac bdt tic (8 electron) thi nguyin tic ciia cdc nguyin td cd khuynhudng liin ki't vdi cdc nguyin tic khdc de dqt dugc cdu hinh electron vicng beciia cdc khi hii'm vdi 8 electron (hodc 2 ddi vdi heli) a lap ngodi cung. Vdi quy tdc bat tir, ngudi ta cd the giai thfch mdt each dinh tinh su hinh thanh cac loai lien ket trong phan tir, dac biet la each viet cdng thiic cau tao trong cac hgp cha't thdng thudng. Vi phan tir la mdt he phiic tap nen trong ahieu trudng hgp quy tdc bat tir td ra khdng ddy du. 66 5 - HN10/NCB II - LI£N KET ION 1. Sir hinh thanh ion a) Ion Trong nguyen tir, sd proton bdng sd electron nen nguyen tir trung hoa dien. Trong phan ling hoa hgc, neu nguyen tir mat bdt hoac thu them electron, nd se trd thanh phdn tir mang dien tich duong hoac am. Phdn tu mang diin dugc tqo ra tic nguyin tic hodc nhdm nguyin tu dugc ggi Id ion. Ion duang (hay cation) : Ta xit su hinh thdnh ion natri tic nguyin tu natri : Nguyen tir natri cd cau hinh electron : Is^ 2s2 2p6 3si va nang lugng ion hod Ij nhd nen d6 mat mdt electron d ldp ngoai ciing de trd thdnh ion mang mdt don vi dien tfch duong. Ta cd the bieu di6n qua trinh dd nhu sau : Na -^ Na+ + e Cac nguyen tir kim loai d6 nhudng 1,2,3 electron d ldp ngoai ciing de trd thanh cac ion mang 1, 2, 3 don vi dien tfch duong. Thf du : Mg -> Mg2+ + 2e Al -^ A13+ + 3e Ion mang dien tich duong dugc ggi la ion duang hay cation. Ngudi ta ggi ten cation kim loai bang each dat trudc ten kim loai tir cation nhu cation liti (Li+), cation magie (Mg2+), cation nhdm (AP+), cation ddng 1 (Cu+), cation ddng 11 (Cu2+),... Ion dm (hay anion) : Ta xet sU hinh thdnh ion flo tic nguyin tic flo : Nguyen tir flo cd cau hinh electron : Is^ 2s2 2p5 va cd do am dien ldn nen flo d6 thu them mdt electron de trd thanh ion mang mdt don vi dien tich am. Ta cd the bieu di6n qua trinh dd nhu sau : F + e ^^ F~ Cac nguyen tir halogen khac va cac nguyen tir phi kim nhu O, S cd the thu them 1, 2 electron va trd thanh cac ion am. Thi du : Cl + e ^ Cl O +2e ^ 02- S + 2e ^ S2- lon mang dien tfch am dugc ggi la ion dm hay anion. Ngudi ta thudng ggi ten cac anion bdng ten gd'c axit tuong ung, thf du cac ion F", Cl", S2- ldn lugt dugc ggi la ion florua, clorua, sunfua. Ion 0^~ dugc ggi la ion oxit. 67 b) Ion dun va ion da nguyen tii Ion dan nguyin tic la ion dugc tao nen tur mdt nguyen tir. Thi du : Li+, Mg2+, A13+, Cu2+, F-,C1-,S2-,... Ion da nguyin tic la ion dugc tao nen hi nhieu nguyen tir hen ket vdi nhau de thanh mdt nhdm nguyen tir mang dien tfch duong hay dm. Thf du, ion amoni (NH4), cac ion gd'c axit nhu ion nitrat (NO3), ion sunfat (804"), ion photphat (PO^),... 2. Sir hinh thanh lien ket ion a) Su tao thanh lien ket ion ciia phan tii 2 nguyen tii Xet su hinh thanh lien ket ion trong phan tir natri clorua (NaCl). Do dac diem cdu tao nguyen tir va theo quy tdc bat tir, khi cac nguyen tir Na va Cl tiep xiic vdi nhau se cd su nhudng va nhan electron de trd thanh cac ion Na+ va Cl~, cd cau hinh electron nguyen tir gid'ng cau hinh electron nguyen tir ciia cac khi hiem Ne va Ar. Cac ion Na+ va Cl" dugc tao thanh cd dien tfch trai da'u, hiit nhau tao nen lien ket ion trong phan tir ciing nhu trong tinh the NaCl. Su hinh thdnh lien ket ion trong phan tir NaCl cd the tdm tdt bang so dd sau : Na + Cl > Na+ + CL Is2 2s2 2p6(3?) Is2 2s2 2p6 3s2^ ^ Is2 2s2 2p6 ls2 2s2 2p6 3s2 3p6 Hai ion dugc tao thanh mang dien tfch ngugc ddu hiit nhau bang luc hiit tinh dien, tao nen phan tu NaCl : Na+ + Cl- -^ NaCl b) Su tao thiinh lien ket ion trong phan tu nhieu nguyen tu Thi du : Phan tif CaCl2. Tuong tu nhu su hinh thanh phan tir NaCl, su hinh thanh lien kdt ion trong phan tir CaCl2 cd the bieu diln bang so dd sau : Cl + Ca + Cl > Cl- + Ca2+ + Q" [Ne]3s2(^ [Ne]3s23i^(@ [Ne] 3s2 ^ [Ne] 3S23F^ [Ne] 3S23{^ [Ne] 3S23F^ Cac ion Ca2+ va Cl tao thanh mang dien tich ngugc ddu hiit nhau bdng luc hiit tinh dien, tao nen phan tit CaCl2 : Ca2+ + 2C1- -^ CaCl2 68 Vay : Liin kit ion la liin kit dugc tqo thdnh do luc hut tinh diin giua cdc ion mang diin tich trdi ddu. Lien ket ion dugc hinh thanh giiia kim loai dien hinh va phi kim dien hinh. Ill - TINH THE VA MANG TINH THE ION 1. Khai niem ve tinh the Tinh the dugc cdu tao tii nhiing nguyen tir, hoac ion, hoac phan tir. Cac hat nay dugc sdp xep mdt each deu dan, tudn hoan theo mdt trat tu nha't dinh trong khdng gian tao thanh mang tinh the. Cac tinh the thudng cd hinh dang khdng gian xac dinh. 2. Mang tinh the ion Xet mang tinh the NaCl : Mang tinh the NaCl cd cdu tnic hinh lap phuong. Cdc ion Na+ va Cl" ndm d cdc mit cua mang tinh the mdt each luan phien. Trong tinh the NaCl, cii mdt ion Na+ dugc bao quanh bdi 6 ion Cl". Ngugc lai, mdt ion Cl" dugc bao quanh bdi 6 ion Na+(hinh 3.1). «i—-1- / / 'ci- -B t- / / Cl %,. »/ •>', TPP^ • Na^ %-/ / / Na* Hinh 3.1. Md hinh mang tinh the natri clorua Tinh the NaCl dugc tao bdi rdt nhieu ion Na+ vd Cl", khdng cd phan tir NaCl rieng biet. Tuy vay, khi viet cdng thiic phan tir ciia mudi natri clorua, de don gian ngudi ta chi viet NaQ. Tuong tu dd'i vdi cdc hgp chat ion khac nhu : KQ, Mga2,... Cling viet nhu vay. 69 3. Tinh chat chung cua hop chat ion 6 dieu kien thudng, cac hgp chdt ion thudng tdn tai d dang tinh the, cd tfnh b6n viing, thudng cd nhifit do ndng chay va nhiet dd sdi kha cao. Cac hgp chat ion chi tdn tai d dang phdn tir rieng re khi chiing d trang thai hoi. Cac hgp chdt ion thudng tan nhieu trong nudc. Khi ndng chay va khi hoa tan trong nudc, chiing ddn dien, cdn d trang thai rdn thi khdng ddn dien. BAI TAP 1- Cac nguyen tir lien ket vdi nhau thanh phan tirde A. chuyen sang trang thai cd nang lugng tha'p hon. B. cd cau hinh electron ciia khi hiem. C. cd cau hinh electron Idp ngoai ciing la 2e hoac 8e. D. chuyen sang trang thai cd nang lugng cao hon. Dap an nao sai ? 2. The nao la nang lugng ion hoa thir nha't ciia nguyen tu" ? Nguyen tii A cd nang luong ion hoa thd nha't Idn hon nang luong ion hoa thd nha't ciia nguyen tuf X, hdi nguyen td nao dl nhudng electron hon ? 3. Hay viet phuong trinh bieu diln su hinh thanh cac ion sau day tU cac nguyen tif tuong irng : Li -^ Li+, Na -^ Na+, Cl -^ Ch Mg -^ IVlg2+, Al -^ A|3+, S ^ S2- 4. Hay vie't cau hinh electron ciia cac ion sau day : Li+, Be2+, F-, 02- 5. Hay giai thich sU hinh thanh lien ket gida cac nguyen tir ciia cac nguyen td sau day : K va Cl, Na va O. 6. Nguyen tif ciia cac nguyen td Na, Mg, Al, S, Cl, F cd the tao thanh ion cd dien tich bang bao nhieu ? 7. Hay cho thi du ve tinh the ion va cho bie't ban chat lUc lien ket trong cac tinh the ion. 8. Cation R+ cd cau hinh electron d phan Idp ngoai ciing la 2p6. a) Viet cau hinh electron nguyen tir ciia nguyen td R. b) Nguyen td R thudc chu ki nao ? Nhdm nao ? Cho biet ten ciia nguyen td. c) Nguyen td R la kim loai hay la phi kim ? 70 (Bdi 17 LIEN K^T CONG HOA TRI • Lien ket cong hoa trj trong phan tur don chat va hdp chat diroc hinh thanh nhirthe nao ? • Sir phan circ trong lien ket cong hoa trj nhu the nao ? I - sa HINH THANH LIEN KET CON G HOA TR! BANG CAP ELECTRON CHUNG 1. Sir hinh thanh phan tir don chat a) Su hinh thanh phan tu H, Nguyen tir H (Z = 1) cd cau hinh electron la Isi, hai nguyen tir H lien ket vdi nhau bdng each mdi nguyen ttr H gdp 1 electron tao thanh mdt cap electron chung trong phan tir H2. Nhu the trong phan tir H2, mdi nguyen tir cd 2 electron, gid'ng cdu hinh electron bfin viing ciia khf hiem heli : H+.H ^ H:H Mdi cha'm ben kf hieu nguyen td bieu di6n mdt electron d ldp ngoai ciing, H : H dugc ggi la cdng thicc electron. Thay hai cham bdng 1 gach, ta cd H - H ggi la cdng thicc cdu tqo. Giiia 2 nguyen tir hidro cd 1 cap electron lien ket bieu thi bdng mdt gach (-), dd la liin kit dan. b) Su hinh thanh phtin tu N, Cdu hinh electron nguyen tir ciia 'H (L-l) la ls2 2s2 2p3, cd 5 electron d ldp ngoai ciing. Trong phan tir nito N2, de dat cau hinh electron ciia nguyen tif khi hiem gdn nhdt (Ne), mdi nguyen tir nito phai gdp chung 3 electron. • NjlN: hay N^ N Cong thdc electron Cong tiiCrc cau tao Hai nguyen tir nito lien ket vdi nhau bdng 3 cap electron lien ket bieu thi bdng ba gach (=), dd la lien kit ba. Lien ket ba nay ben nen d nhiet do thudng, khf nito rdt ben, kem boat ddng hod hgc. Lien ket dugc hinh thanh trong phan tir H2, N2 vira tnnh bay d tren la lien ket cdng hoa tri. 71 Lien ki't cdng hod tri Id lien ki't dugc hinh thdnh giita hai nguyin tut bang mgt hay nhieu cap electron chung. Mdi cap electron chung tao ndn mdt lidn ket cdng hoa tri. Cac phdn tir H2, N2 tao nen tii hai nguydn tvr cua ciing mdt nguyen td (cd do dm didn nhu nhau), ndn cac cap electron chung khdng bi hiit lech vd phia nguyen ti nao. Do dd, lien ket trong cac phdn tit dd khdng bi phdn cue. Dd la lien ki't cdng hod tri khdng cue. 2. Sir hinh thanh phan tir hop chat a) Sir hinh thanh phan tir HCI Trong phan tit hidro clorua, mdi nguydn tuf (H va Cl) gdp 1 electron tao thanh 1 cap electron chung de tao ndn mdt lien kdt cdng hoa tri. Do dm didn cua clo la 3,16 ldn hon do dm didn cua hidro la 2,20 nen cap electron lien kdt bi lech v^ phfa clo, lien ket cdng hod tri nay bi phdn cue. H + Ci: -^ H :Cl: hay H-Cl Cong thCfc electron Cong thitc cau tao Trong cdng thdc electron ciia phdn tit cd cue, ngudi ta dat cap electron chung lech vd phfa kf hidu cua nguyen tir cd do am dien ldn hon. Thi du : H :C1 Lien ket cdng hod tri trong dd cap electron chung bi lech ve phfa mdt nguyen tit dugc ggi la lien ki't cdng hod tri co cue hay liin kit cdng hod tri phdn cue. b) Su hinh thanh phan tu CO2 (cd caiu tao thang) Cdu hinh electron nguyen tit cua C (Z = 6) la ls2 2s2 2p2, nguyen tir cacbon co 4 electron d ldp ngoai cung. Cdu hinh electron nguyen tir ciia O (Z = 8) la ls2 2s2 2p4, nguyen tit oxi cd 6 electron d ldp ngoai cung. Trong phan tir CO2, nguydn tit C ndm giiia 2 nguyen tii O va gdp chung vdi mdi nguyen tir O hai electron, mdi nguyen tii O gdp chung vdi nguydn hi C hai electron tao ra 2 lien kdt ddi. Ta cd : :6::C::0 : hay 0 = C = 0 Cong thUc electron Cong thUc cau tao Nhu vay, mdi nguydn tit C hay O ddu cd 8 electron d ldp ngoai ciing, dat cdu hinh bdn viing cua khf hidm. Do dm dien cua oxi (3,44) ldn hon do dm dien 72 cua C (2,55) ndn cap electron chung lech ve phia oxi. Liin ki't giUa nguyin tic oxi vd cacbon Id phdn cue, nhung phan tir CO2 cd cau tao thang nen do phdn cue cua hai lidn ket ddi (C = O) triet tieu nhau, kit qud Id todn bd phdn tic khong bi phdn cue. c) Lien ket cho - nhan Trong mdt sd trudng hgp, cap electron chung chi do mdt nguyen tir ddng gdp thi lidn ket giiia hai nguyen tir la liin kit cho - nhdn. Thi du : Dd'i vdi phan tir SO2 cdng thiic electron, cdng thij-c cdu tao cd the' bieu didn nhu sau : ..s... A :g- O: O O Cong thCfc electron Cong thUc cdu tao Nguyen tir S cd 6 electron d ldp ngoai cimg. Khi hinh thanh phan tir SO2, nguydn tii S da dung 2 electron ddc than gdp chung vdi hai electron ddc than ciia mdt trong hai nguydn tir oxi. Nguyen tir S sir dung mdt cap electron de dung chung vdi nguydn tir oxi cdn lai. Trong cdng thiic cau tao, ngudi ta bieu dien cap electron chung bdng mdt gach nd'i, cap electron cho - nhan bdng mdt mui ten cd chieu hudng ve phfa nguydn tir nhan. 3. Tinh chat cua cac chat co lien ket cong hoa tri Cac chat ma phan tir chi cd lien ket cdng hod tri cd the' la chat rdn nhu dudng, luu huynh, iot,..., cd the la chdt long nhu : nudc, ancol,... hoac chdt khi nhu khf cacbonic, clo, hidro,... Cdc chdt cd cue nhu ancol etylic, dudng,... tan nhieu trong dung mdi cd cue nhu nudc. Phdn ldn cdc chat khdng cue nhu iot, cdc chdt hiiu co khdng cue tan trong dung mdi khdng cue nhu benzen, cacbon tetraclorua,... Ndi chung, cac chdt chi cd lidn ket cdng hoa tri khdng cue khdng ddn dien d mgi trang thai. II - LIEN KET CON G HO A TRI VA SIS XEN PHU CAC OBITAN NGUYtN Tif 1. Sir xen phu cua cac obitan nguyen tir khi hinh thanh cac phan tir don chat a) Su hinh thanh phan tir H2 De' hinh thanh lien ket giiia hai nguyen tir H trong phan tir hidro, hai obitan 1 s cua hai nguyen tir H xen phu vdi nhau tao ra mdt vung xen phii giiia hai hat nhan nguydn tir. Xdc sudt cd mat cua cac electron tap trung chii yeu d khu vuc giua 73 hai hat nhan. Vi vay, ngoai luc day tuong hd giua hai proton va hai electron con cd luc hiit giiia cac electron vdi hai hat nhan hudng ve tam phan tir (hinh 3.2). 1s Is Sir xen phu cua 2 obitan Is cua hai nguyen ttJr hidro Hinh 3.2. Suhinh thanh phan ti^ hidro Khi hai hat nhan cd khoang each d = 0,074 nm, cac luc hiit va liic day cdn bdng nhau (d dugc ggi la khoang each can bdng hay do dai ciia lien ket H - H). O khoang each can bdng tren, phan tir H2 cd nang lugng thap hen tdng nang lugng ciia hai nguyen tir rieng re. Dd la nguyen nhan cua su hinh thanh lien ket cdng hoa tri giiia hai nguyen tir H va la mdt lien ket hod hgc ben. b) Su hinh thanh phan tii CL De giai thfch su hinh thanh lien ket Cl-Cl, cd the dua vao cau hinh electron ciia mdi nguyen tir clo : c: [nj m \n\n\n\ \n\ inini t Is' " 2s'^ 2p'' 3s^ 3p^ Su hinh thanh lien ket giua hai nguyen tir clo la do su xen phu giiia hai obitan p chiia electron ddc than cua mdi nguydn tu clo (hinh 3.3). Cl Cl Cl - Cl Hinh 3.3. Si/xen phij 2 obitan p tao thanh lien ket Cl-Cl trong phan tCt CI2 2. Sir xen phu cua cac obitan nguyen tir khi hinh thanh cac phan tii hop chat a) Sir hinh thanh phan tir HCI Phan tir cua hgp chat dugc hinh thanh tir cac nguyen tif cua cac nguyen td khac nhau, nhu phan tir HCI. 74 Lien ket hod hgc trong phan tir hgp chdt HCI dugc hinh thanh nhd su xen phu giita obitan Is cua nguyen tir hidro va obitan 3p cd 1 electron ddc than ciia nguyen tu clo (hinh 3.4). Cl H-CI Hinh 3.4. Suxen phCi obitan 1s cua hidro vdi obitan 3p cCia nguyen tCr Cl tao lien ket H-CI b) Sir hinh thanh phan tu H2S Su hinh thanh phan tir H2S cd thd md ta bang hinh anh xen phii giiia obitan Is ciia cac nguyen tir hidro va 2 obitan p cua nguyen tir luu huynh. Ldp ngoai cung cua nguydn tir S cd cdu hinh electron 3s2 3p4. Tren 2 obitan p cd 2 electron ddc than. Hai obitan nay xen phu vdi 2 obitan Is cd electron ddc than ciia 2 nguydn tir H tao nen 2 lien ket S-H (hinh 3.5). Hinh 3.5. Su xen phO cOa hai AO Is cua hai nguyen tH hidro BAI TAP vdi hai AO 2p cua nguyen tCt S tao hai lien ket S-H 1 Chon djnh nghTa dung nha't ve lien ket cdng hoa trj. Lien ket cong hoa tri la lien ket A. gida cac phi kim vdi nhau. B. trong dd cSp electron chung bi lech ve mot nguyen tir. C. dugc hinh thanh do sU diing chung electron cua 2 nguyen tir khac nhau. D. dugc hinh thanh giu'a 2 nguyen tir bang mot hay nhieu cap electron chung. 2. Hay giai thich su hinh thanh cap electron lien ket gida nguyen tir C va cac nguyen td H trong phan tir CH4, gida nguyen tir O va cac nguyen tCr H trong phan td H2O, gida nguyen tu" S va cac nguyen tir H trong phan tir H2S. 3. Giai thich su hinh thanh cap electron lien ket giura hai nguyen tir N trong phan tir N2, giura nguyen tir H va nguyen tir Cl trong phan tir HCI. 4. Giai thich sU hinh thanh lien ket cdng hoa tri bang suxen phii cac obitan trong phan tir HCI. 5. Hay viet cong thdc electron va cdng thdc cau tao ciia cac phan tir sau day : H2, HCI, H2O, CI2, NH3, CH4. 6. X, Y, Z la nhufng nguyen td cd sd don vj dien tich hat nhan la 9, 19, 8. a) Viet cau hinh electron nguyen td cua cac nguyen td dd. b) Du doan kieu lien ket hoa hoc cd the' cd gida cac cSp X va Y, Y va Z, X va Z. 75 mi 18 SaUVI HOA CAC OBITAN NGUYEN Tir. Sir HINH THANH LIEN KET DON, LIEN KET DOI VA LIEN KET BA • Khai niem ve sir lai hoa cac obitan nguyen tir. • Mot so kieu lai hoa dien hinh. • Van dung kieu lai hoa de giai thich dang hinh hoc cua phan tur. • The nao la lien ket ddn, lien ket doi va lien ket ba. • The nao la lien ket xich ma (a), lien ket pi (n) ? Su lai hoa cac obitan nguyen tCr la khai niem quan trgng nhat cCia thuyet hoahudng, dugc Pau-linh dUa ra nam 1931 de giai thich sU dinh hudng cung nhucCia lien l """