Daca la
80 g.. avem... 96,353 x 10la23 e- s
40 g.................. a e- s
=> a = 48,1765 x 10la23
daca la
80 g.. avem... 144,528 x 10la23 e- p
40 g.................. b e- p
=> b = 72,264 x 10la23
n = N / N.A =
n e- s = 48,1765 x 10la23 / 6,022x10la23 = 8 e- s
n e- p = 72,264 x 10la23 / 6,022x10la23 = 12 e- p
=> total e- = 20
=> Z = 20
1s2 2s2 2p6 3s2 3p6 4s2
gr. II. A, per. 4 => X = Ca