Clor Z=17 A=35 17p+ 18n0 17e-
Calciu Z=20 A=40 20p+ 20n0 20e-
Potasiu Z=19 A=39 19p+ 30n0 19e-
Brom Z=35 A=80 35p+ 45n0 35e-
Oxigen Z=8 A=16 8p+ 8n0 8e-