A.
1-F
2-A
3-F
4-F
5-F
B.
1-gaze nobile
2-ultimul
3-straturi ocupate cu electroni
4-18
1.
a.
..... 3s2 3p6 -2e- => ...... 3s2 3p4
=> 1s2 2s2 2p6 3s2 3p4
=> gr. 16 (VI-A) , per. 3
=> Z = 2+2+6+2+4 = 16
b.
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p4
=> gr. 16 (VI-A) , per. 5
=> Z = 52
c.
1s2 2s2 2p6 3s2 3p6 4s1 3d5
gr. 6 (VI-B), per. 4
d.
1s2 2s2 2p6 3s2 3p6 4s2 3d6
gr. 8 (VIII-B) , per. 4
Z = 26
2.
masa unui atom 1,67×10la−27 kg
=> Ar = 7,968x10la-26 kg/1,67x10la-27 kg
= 48 u.a.m.
A = Z + n0, Z/n0 = 11/13
=> Z = 0,846n0
=> 48 = 0,846n0 + n0 => n0 = 26
=> Z = A - n0 = 48 - 26 = 22
=> 1s2 2s2 2p6 3s2 3p6 4s2 3d2
gr. 4 (IV-B) , per. 4
