CHNG I: NGUYN T A. Kin thc cn nh I. Thnh phn cu to nguyn t K hiu p n e in tch 1+ 10 Khi lng 1u 1u 5,5.10-4 u

Proton Ntron V nguyn t Electron II. in tch v s khi ca ht nhn in tch ht nhn (Z+):

Cu to nguyn t Ht nhn nguyn t

Z = Tng s ht proton = Tng s ht electron

S khi ca ht nhn (A):

A=Z+N

Nguyn t khi trung bnh:

A=

aA+bB 100

a, b l % tng ng ca ng v A, B

ng v: l nhng nguyn t c cng s proton nhng khc nhau v s ntron, do chng c s khi khc nhau

V d: Hidro c 3 ng v:-

Hin tng ng v gii thch c v sao nguyn t khi ca 1 nguyn t li l s thp phn. V d Cl: 35,5; Cu: 63,54; . iu kin bn ca 1 nguyn t: 1 1,52

-

III.

Cu trc v electron ca nguyn t

1. Obitan nguyn t

-

Obitan nguyn AO t l vng khng gian quanh ht nhn m c xc sut tm thy electron l ln nht (>95%) Mi AO ch cha ti a 2e S AO ti a ca lp n l n2, s e ti a trong lp n l 2n2

2. Lp v phn lp electron S th t lp K hiu ca lp S e ti a (2n2) ca lp S phn lp trong lp 1 K 2 1 2 L 8 2 3 M 18 3 4 N 32 4

Tn phn lp 1s 2s, 2p 3s, 3p, 3d S e ti a phn lp 2 2, 6 2, 6, 10 3. S phn b electron trong nguyn t tun theo 4 nguyn tc v quy tc sau lng t thp n cao.b. Quy tc Kleckopski: Mc nng lng AO tng dn theo trnh t sau:

4s, 4p, 4d, 4f 2, 6, 10, 14

a. Nguyn l vng bn: trng thi c bn, trong nguyn t cc e chim ln lt nhng AO c mc nng

1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 7s 5f 6d. c. Nguyn l Pauli: Trong 1 AO ch cha ti a 2e v 2e ny c chiu t quay khc nhau (k hiu bng 2 mi tn ngc chiu nhau) d. Quy tc Hund: Trong cng 1 phn lp, cc electron s phn b trn cc AO sao cho s electron l ti a v cc electron ny c chiu t quay ging nhau. VD: C (Z=6) 1s2 2s2 2p2

4. Cu hnh electron ca nguyn t -

Cu hnh electron ca nguyn t dng m t cc electron phn b nh th no trong cc lp, phn lp ca nguyn t.

Ch : + Cu hnh electron i vi 20 nguyn t u, cu hnh electron ph hp vi mc nng lng (t H n Ca) + Bt u t nguyn t th 21, cu hnh electron khng trng vi mc nng lng AO VD: Fe (Z=26): 1s22s22p63s23p64s23d6 thay v vit 1s22s22p63s23p63d64s2 + Cu hnh electron ca 1 s nguyn t nh Cu, Cr, Pd c ngoi l i vi electron lp ngoi cng (nhm t cu trc electron bn nht: bo ha hay bn bo ha d5 hay d10) VD: Cu (Z=29): 1s22s22p63s23p63d94s2 => vit ng l: 1s22s22p63s23p63d104s1 5. c im ca lp electron ngoi cng Cu hnh electron lp ngoi cng S electron lp ngoi cng Tnh cht ha hc in hnh B. Bi tp ns1 ns2 ns2np1 1, 2, 3 Kim loi (tr B) ns2np2 4 C th l kim loi hoc phi kim ns2np3 ns2np4 ns2np5 5, 6, 7 Phi kim ns2np6 8 Kh him

Dng 1: Tm s khi, phn trm cc cc ng v, nguyn t khi v nguyn t khi trung bnh Nguyn tc:

+ Gi khi th: + Gi th:

l nguyn t khi trung bnh; a, b l thnh phn % tng ng ca cc ng v A, B; A, B l nguyn t

l nguyn t khi trung bnh; a, b l t l s nguyn t ca cc ng v A, B; A, B l nguyn t khi

VD1: Cho hai ng v ca hidro v hai ng v ca clo vi t l % s nguyn t chim trong t nhin nh sau: . a. Tnh nguyn t khi trung bnh ca mi nguyn t b. C th c bao nhiu loi phn t HCl khc nhau c to nn t hai ng v ca hai nguyn t ? c. Tnh phn t khi ca mi loi phn t ni trn Bi gii: a.

b. C 4 phn t khc nhau c hnh thnh t hai ng v ca hai nguyn t trn:1

H37Cl (M1); 1H35Cl (M2); 2H37Cl (M3); 2H35Cl (M4)

c. M1 = 1 + 37 = 38; M2 = 1+35 36; M3 = 2+37 = 39; M4 = 2+35 = 37

VD2: Nguyn t khi trung bnh ca ng bng 63,546. Trong t nhin ng c hai ng v Tnh t l % s nguyn t ca ng v Bi gii: Gi % mi ng v tng ng l x, y ta c x + y = 100 (1) Theo CT tnh KLNTTB (2) = 72,7% tn ti trong t nhin.

.

Gii h phng trnh (1,2) ta c x = 72,7% => % Bi tp p dng:

63 65 Bi 1: ng t nhin gm hai ng v 29 Cu; 29 Cu . Khi lng nguyn t trung bnh ca

ng l 63,546. Tnh % khi lng ca ng v

65 29

Cu trong CuSO4 (cho O = 16; S = 32)

Bi 2: S khi trung bnh ca Ag l 107,87, trong t nhin bc c hai ng v, trong ng v107 47

C chim 56% v s cc nguyn t. Xc nh s khi ca ng v cn li v

tnh khi lng nguyn t tuyt i ca ng v . Bi 3: Trong t nhin , nguyn t Argon tn ti ba ng v : (0,31%);38 18 40 18

Ar (99,63%);

36 18

Ar

Ar (0,06%). Tnh nguyn t khi trung bnh ca Ar?

Cu 4: Nguyn t Argon c 3 loi ng v c s khi bng 36; 38 v A. Phn trm s nguyn t tng ng ca 3 ng v ln lt bng 0,34%; 0,06% v 99,6%. Bit 125 nguyn t Ar c khi lng 4997,5 vc. S khi A ca ng v th 3 l: A. 40 B. 40,579

C. 3981

D. 39,8

Cu 5: Brom c 2 ng v l

Br v

Br . Trong t nhin nguyn t khi trung bnh

ca brom l 79,92 u. % theo s nguyn t ca 2 ng v trn ln lt l A. 54% v 46% 49,95%. Dng 2: Da vo s ht c bn trong nguyn t xc nh Z v tn nguyn t. VD1: Mt nguyn t R c 3 ng v X, Y, Z. Bit tng s ht ca 3 ng v l 129, s ntron trong ng v X hn ng v Y 1 ht, ng v Z c s proton bng s ntron. Xc nh in tch ht nhn nguyn t R v s khi ca 3 ng v X, Y, Z Gii: Ta c: (P + E + NX) + (P + E + NY) + (P + E +NZ) = 129 (2Z + NX) + (2Z + NY) + (2Z + NZ) = 129 7Z + NX + NY = 129 (1)

B. 46% v 554%

C.49,95% v 50,05%

D. 50,05% v

Mt khc c

NX NY = 1 (2)

Gii h pt (1,2) ta c 7Z + 2NX = 130

. 1,52

iu kin ht nhn bn: 1

1

1,52

=> 12,9 Z 14,4 Ta c:

P NX AX Kt lun Vy: Z = 14; NX = 16; Ax = 30 AZ = Z + NZ = 28;

13 19,5 32,5 Loi

14 16 30 ng

AY = Z + NY = 29

VD2: Nguyn t nguyn t M c 82 ht c bn (proton, ntron v electron), nguyn t nguyn t Y c 52 ht c bn, s ht mang in nhiu hn s ht khng mang in l 16. Mv Y to hp cht MYa trong c 77 proton. Xc nh cc nguyn t M, Y v hp cht MYa. Gii : - Nguyn t Y : P + E + N = 52 v (P + E) N = 16 P = E = 17 v N = 18. Y l - Nguyn t M : PM + EM + NM = 82 v PM = EM. Mt khc 1 N 1,52 nn ta c 23,3 < PM < 27,3. P35 17

Cl .

Trong hp cht MYa c tng s proton : PM + aP = PM + 17a = 77 2,9 < a < 3,2 Vy a = 3 v PM = 26; NM = 30 v k hiu nguyn t M : Bi tp p dng Bi 1: Mt nguyn t R c tng cc loi ht bng 115 s ht mang in tch nhiu hn s ht khng mang in l 25. Hy xc nh s proton, s khi v vit cu hnh electron ca R v cho bit R l kim loi hay phi kim ? Ly hai phng trnh phn ng ho hc minh ho.22Bi 2 : Mt hp cht A to bi hai ion X2+ v Y Z3 . Tng s electron ca Y Z3 - bng 3256 26

Fe v hp cht l FeCl3.

ht, Y v Z u c s proton bng s ntron. Hiu s ntron ca hai nguyn t X v Y bng 3 ln s proton ca Z. Khi lng phn t ca A bng 116 u. Xc nh X, Y, Z v cng thc phn t ca A. Bi 3. Nguyn t ca nguyn t X c tng s cc ht l 180. Trong tng s cc ht mang in nhiu gp 1,432 ln tng s ht khng mang in. Xc nh s hiu nguyn t, s khi ca nguyn t X.

Bi 4. Tng s ht p, n, e ca mt nguyn t A l 16, trong mt nguyn t B l 58, trong mt nguyn t D l 180. Tm s p, n v s khi ca cc nguyn t A, B, D. Bit rng s chnh lch gia s khi v khi lng nguyn t trung bnh khng qu 1 n v. Bi 5. Tng s ht proton, ntron, electron trong 2 nguyn t kim loi A v B l 142, trong tng s ht mang in nhiu hn tng s ht khng mang in l 42. S ht mang in ca nguyn t B nhiu hn ca A l 12. Dng 3 : Da vo cu hnh electron nguyn t xc nh nguyn t l phhi kim hay kim loi Ch : s electron lp ngoi cng (n) + n = 1, 2, 3 => nguyn t kim loi + n = 4 => nu nguyn t thuc chu k nh l phi kim ; nguyn t thuc chu k ln l kim loi + n = 5, 6, 7 => nguyn t phi kim + n = 8 => nguyn t kh him VD1 : Nguyn t A khng phi kh him, nguyn t ca n c phn lp ngoi cng l 3p. Nguyn t nguyn t B c phn lp ngoi cng l 4s. a. Nguyn t no l kim loi, nguyn t no l phi kim b. Xc nh cu hnh electron ca A, B v tn ca chng. Bit tng s electron ca 2 phn lp ngoi cng ca chng l 7.c. S phn b electron trn cc AO ca cc nguyn t K (Z=19) v Ca (Z=20) c c

im g ? Gii:a. Nguyn t A c phn lp ngoi cng l 3p => A c th l kim loi (3p1, 3p2) ; c th

l phi kim (3p3, 3p4, 3p5)Nguyn t B c phn lp ngoi cng l 4s => B l kim loi b. Tng s electron 2 phn lp ngoi cng ca A v B l 7 Nu ca A l 4s1 => B l 3p6 => B l kh him Nu A l 4s2 => B l 3p5 => B l phi kim A: 1s22s22p63s23p64s2 (A l Ca) B: 1s22s22p63s23p5 (B l Cl)

c. c im chung: u b qua phn lp 3d m electron in ngay vo phn lp 4s VD2: Tng s p, n, e trong nguyn t ca 1 nguyn t l 34. a. Hy m t cu to nguyn t ca nguyn t . b. Vit cu hnh electron ca nguyn t trn v xc nh v tr ca n trong bng HTTH c. Xc nh tnh cht c bn ca nguyn t Gii: a. ta c: 2Z + N = 34 N = 34 2Z (1) Z N 1,52Z (2)

iu kin bn ca 1 nguyn t: Thay (1) vo (2) c

Z 34 2Z 1,52Z => 9,7 Z 11 => Z = 10, 11

Z = 10 (Ne) NX = 14 AX = 24 ( MNe = 20,18) loi Z = 11 (Na) NX = 12 AX = 23 ng. b. Cu hnh electron: 1s22s22p63s1 => X thuc chu k 2; nhm IA c. X l cht kh mnh hay c tnh kim loi mnh Bi tp p dng: Bi 1: 1. Trnh by v gii thch s bin thin tnh kim loi v phi kim ca cc nguyn t trong chu k v trong phn nhm chnh. 2. C 3 nguyn t X, Y, Z c s hiu nguyn t ln lt l: 17; 18; 19. Hy xc nh X; Y, Z c th l kim loi, phi kim hay kh him ? Bi 2: Hp cht ion cu to t cc ion n nguyn t M+ v X2-. Trong phn t M2X c tng s ht (p, n, e) l 140. Trong s ht mang in nhiu hn s ht khng mang in l 44 ht. S khi ca ion M+ ln hn s khi ca ion X2- l 23. Tng s ht (p, n, e) trong ion M+ nhiu hn trong ion X2- l 31 ht. Vit cu hnh electron ca cc ion M+ v X2-, ca M v X. Xc nh v tr ca M v X trong bng tun hon cc nguyn t ho hc. Bi 3: Mt hp cht to thnh t M+ v X 2 . Trong phn t M2X2 c tng s cc ht proton, 2 ntron, electron bng 164, trong s ht mang in nhiu hn s ht khng mang in l 52. S khi ca M ln hn s khi ca X l 23 (u). Tng s ht trong M+ ln hn trong X 2 l 7 ht. 2 a. Xc nh cng thc M2X2. Vit cu hnh electron ca M+ v cng thc electron ca X 2 . 2 b. Cho M2X2 tc dng vi nc. Vit phng trnh phn ng v nu phng php nhn bit sn phm.