Cl, Z=17 => 1s2/2s22p6/3s23p5 +1e => 1s2/2s22p6/3s23p6, accepta 1e, (nemetal) , grupa a VII-a , perioada 3, valenta 1, este al 17-lea in S.P
Mg, Z=12, => 1s2/2s22p6/3s2 -2e => 1s2/2s22p6/, cedeaza 2e (metal), grupa a II-a, perioada 3, valenta 2, este al 12-lea in S.P
Ca, Z=20 => 1s2/2s22p6/3s23p6/4s2 -2e => 1s2/2s22p6/3s23p6/, cedeaza 2e(metal) , grupa a II-a , perioada 4, valenta 2, este al 20-lea in S.P
Br, Z=35 => 1s2/2s22p6/3s23p63d10/4s24p5 + 1e =>
1s2/2s22p6/3s23p63d10/4s24p6/, accepta 1e(nemetal), grupa a VII-a , perioada 4, valenta 1, este al 35-lea in S.P
I, Z=53, 1s2/2s22p6/3s23p63d10/4s24p64d10/5s25p5 + 1e => 1s2/2s22p6/3s23p63d10/4s24p64d10/5s25p6/ , accepta 1e(nemetal), grupa a VII-a , perioada 5, valenta 1, este al 53-lea in S.P
P, Z=15, 1s2/2s22p6/3s23p3 + 3e => 1s2/2s22p6/3s23p6/, accepta 3e (nemetal), grupa a V-a , perioada 3, valenta 3, este al 15-lea in S.P
