Na p=11, e= 11, n=23-11=12, Z=+11
Mg p=12, e= 12, n = 24-12=12, Z=+12
Al p=13, e= 13, n= 27-13= 14. Z= +13
Si p= 14, e= 14, n= 28-14=14, Z = +14
P p= 15, e= 15, n = 31-15= 16, Z = +15
S p= 16, e= 16, n = 32-16= 16, Z = +16
Cl p=17, e= 17, n = 35-17=18, Z = +17
Ar p=18, e= 18, n = 40-18=22, Z = +18
n - нейтроны (нейтральные), а не нейроны (клетки нервной ткани)