straturi : K(1) L(2) M(3)
Al : Z = 13 1s²2s²2p⁶3s²3p¹ 2e⁻ 8e⁻ 3e⁻
Si : Z = 14 1s²2s²2p⁶3s²3p² 2e⁻ 8e⁻ 4e⁻
P : Z = 15 1s²2s²2p⁶3s²3p³ 2e⁻ 8e⁻ 5e⁻
S : Z = 16 1s²2s²2p⁶3s²3p⁴ 2e⁻ 8e⁻ 6e⁻
Cl : Z = 17 1s²2s²2p⁶3s²3p⁵ 2e⁻ 8e⁻ 7e⁻
fiecare strat are un substrat s (cu cel mult 2e⁻) ; 1 substrat p (cu cel mult 6e⁻)
strat 1 are 1 substrat (s)
strat 2 are 2 substraturi (s+p)
strat 3 are 3substraturi (s+p+d)
