IV.
a) 6e- tip s + 8e- tip p
=> 1s2 2s2 2p6 3s2 3p2 => Z = (2+2+6+2+2) = 14
b)
2e- in substratul 4d
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d2
=> Z = (2+2+6+2+6+2+10+6+2+2) = 40
c)
11 e- in stratul 3
1s2 2s2 2p6 3s2 3p6 4s2 3d2
=> Z = (2+2+6+2+6+2+2) = 22
