a) nu avem ce calcula aici, le luăm dintr-un tabel periodic
S= 32, C= 14, P = 31, Mg= 24, Zn= 65, Al= 27.
b) M H2 = 2AH = 2 x 1= 2g/mol
M N2= 2AN = 2 x 14= 28g/mol
M Br2= 2ABr = 2 x 80= 160g/mol
M Cl2= 2ACl = 2 x 35,5= 71g/mol
M F2= 2AF = 2 x 19= 38g/mol
M O2 = 2 AO = 2 x 16 = 32 g/mol