2.30. C.
2.31. C. 2.32. D. 2.32. D. 2.33. B.
2.34. Nguyen td photpho d d sd 15, chu ki 3, nhdm VA. Photpho la mdt phi kim vdi 5 electron d ldp ngoai cung.
+ Photpho de nhdn them 3 electron dl cd dugc ldp electron ngodi cung cua khf hiem kripton dftng sau nd nhu trong hgp chat Na3P.
+ Trong cac hgp chat cua photpho vdi oxi, photpho cd thi thi hien hod tri cao nhd't bdng 5 : trong P2O5 i;ay H3PO4.
+ Trong hgp chd't vdi hidro, photpho thi hien hod tri 3 : PH3
+ Oxit cao nhd't cua photpho tac dung vdi nudc thi hien tfnh chdt cua oxit axit.
P2O5 + 3H2O -^ 2H3PO4
2.35. Do dm dien bilu thi kha ndng hut electron cua nguyen tft nguydn td hoa hgc. Do dm dien cdng ldn thi kha ndng hut electron cang ldn (ldn nhdt la nguyen td flo). Do dm dien cd lien quan chat che ddn tinh kim loai va phi kim. Dd dm dien cdng ldn thi tfnh phi kim cang manh, tinh kim loai cang yeu.
Trong mdt chu ki dd dm dien cua nguyen tft cdc nguyen td tdng ddn khi di theo ehilu tdng cfta dien tich hat nhdn, trong chu ki 3 do dm dien cua nguyen tft cac nguyen td tdng ddn khi di tft trdi sang phai. Dd dm dien thdp nhd't bdng 0,93 d nguyen tft nguyen td natri, cao nhd't bdng 3,16 d nguyen tft nguyen td clo.
Trong mdt nhdm A do dm dien cua nguyen tft cdc nguyen td giam ddn khi di theo ehilu tdng dien tfch hat nhdn, trong nhdm VIIA do dm dien giam ddn khi di tft tren xudng dudi. Dd dm dien cao nhdt la d nguyen tft nguyen td flo (3,98) va thdp nhdt d nguyen td atatin (2,20). Atatin da thi hien tfnh chdt cua mdt kim loai, trong khi dd flo la phi kim manh nhdt.
Chu ki 3 Do am dien Nhom VIIA Do am dien Na 0,93 F 3,98 Mg 1,31 01 3,16 Al 1,61 Br 2,96 Si 1,90 I 2,66 P 2,19 At 2,20 S 2,58 Ci 3,16 Ar - Bai 14
LUYEN TAP CHUONG 2
9 "7 fi 0 f\ 0
2.36. Cdu hinh electron nguyen tft cua X la : Is 2s 2p 3s 3p 4s vdi 2 electron
d ldp eletron ngoai cung vi thd X la mdt kim loai. Cdu hinh electron cua ion X "^ la : Is 2s 2p 3s 3p
Tft cdu hinh electron nguyen tft cua X, dl dang kit luan dugc nguyen td X thudc d sd 20, chu ki 4, nhdm IIA.
2.37. D. 2.38. D. 2.38. D. 2.39. A.
2.40. Cdu hinh electron nguyen tft cua X la : Is^ 2s^ 2p^ 3s^ 3p^ 3d^ 4s^. Nhu
vdy, X thudc d sd 22, chu ki 4, nhdm IVB va la kim loai. Ion X "^ hodc X'^* tao thanh la do nguyen tft X mat hai hodc 4 electron. Cdu hinh electron cua cac ion :
X^^ : Is^ 2s^ 2p^ 3s^ 3p^ 3d^ X * ^ l s 2 2s2 2p^3s2 3p^
2.41. Cd'u hinh electron nguyen tft cua Y la : Is^ 2s^ 2p^ 3s^ 3p^. Nguyen td Y d d
sd 18, chu ki 3, nhdm VIIIA. Ddy la mdt nguydn td khf hidm (Ar) cd cdu hinh electron nguyen tft bin viing nen khdng tdn tai hgp chd't cfta Y trong dd Y tdn tai d dang ion.
2.42. Cation R"^ tao thanh tft nguyen tft R do mdt di 1 electron. Cd thi xdy dung cdu
hinh electron nguyen tft cfta R bang each them vao cdu hinh electron cua R"*" mdt electron. Electron them vao dugc phdn bd vao phdn ldp 4s (ngay sau 3p). a) Cd'u hinh electron cua R la : Is 2s 2p 3s 3p 4s
b) Nguyen td R thudc chu ki 4, nhdm IA va la kim loai vi chi cd 1 electron duy nhd't d ldp electron hod tri. R la nguydn td kali.
c) Tinh chd't hoa hgc ddc trung nhd't cua kali la dl nhudng electron trong cac phan ftng hod hgc.
- Khi dl K ngoai khdng khi, anh kim mdt di nhanh chdng do phan ftng : 4K + 0 2 ^ 2 K 2 0
- Cho mdt mdu nhd K vao nudc, phan ftng ddy hidro xay ra manh liet: 2K + 2H2O ^ 2KOH + H2t
d) Anion X tao ra tft nguyen tft X do nhdn 1 electron. Do dd, cd'u hinh electron cua X dugc tim tft cd'u hinh cua X bdng each bdt di 1 electron. Ta cd cdu hinh electron nguyen tft cua X la : Is^ 2s^ 2p^ 3s^ 3p^. Ddy la nguyen td clo.
2.43. Hai kim loai cung d nhdm IIA nen cd cung tfnh chd't hod hgc, cung thi
hien hod tri 2 va cd the thay bdng mdt kim loai tuang duang M. Kim loai tuang duang M cd khdi lugng mol nguyen tft ndm trong khoang gia tri khd'i lugng mol nguyen tft cua hai nguyen td cdn tim.
Ta cd phuang trinh hod hgc :
M + 2HC1-> MCI2 + H2t
Theo phuang trinh hod hgc, sd mol hai kim loai (hay sd mol kim loai tuang duang) bdng sd mol hidro = 3,36 dm^/22,4 dm'^/mol = 0,15 mol.
4 4 p
Khd'i luang mol nguyen tft trung binh cua M la : —-—^—= 29 33 g/mol
0,15 mol ' thudc khoang khd'i lugng mol nguyen tft eua magie va canxi. Vdy hai kim loai cdn tim la Mg va Ca.
Chucmg 3 . _ ^ _ _ _ ^ _ , . . ^ _