Z=42---> are 42 electroni si 42 protoni
A=p+n--> A= 42+54 =96 NUMAR DE MASA
1atom are 42e-
1mol atomi are 6,023x10²³ atomi...si...42x6,023x10²³ e
niu(n)=4,8g/ 96g/mol=0,005mol element monoatomic---.>
1molatomi.........42x6,023X10²³ e
0,005mol............N= 0,005X42X6,023X10²³ electroni
