Odpowiedź:
a) Ca- 40
Br- 80 * 2 = 160
40/160 = 1:4
b)N-14*2=28
O-16*5=80
28/80 = 7:20
c)S-32
O- 16*3= 48
32/48 = 2:4
d)Al-27*2=54
S- 32*3= 96
54/96 = 9:16
