C are Z = 6 si A = 12 => nr neutronilor = 6
12 g C.......6 * 6,023 * 10 la 23 neutroni
10 g C............x neutroni x = 30,115 * 10 la 23 neutroni
Mg are Z=12 si A = 24=>nr neutroni = 12
24 g Mg........12 * 6,023 * 10 la 23 neutroni
12 kg Mg=12000 g Mg................x neutroni x = 36,138 * 10 la 26 neutroni
Cu are Z=29 si A=64=>nr neutroni = 35
1 mol Cu........35 * 6,023 * 10 la 23 neutroni
5 moli Cu.................x neutroni x = 1.05403 * 10 la 26 neutroni
