Respostas

2014-03-27T21:10:09-03:00
P=Z=e

Prótons= 83
Eletrons=83

Neutrons= 209-83 = 163

2014-03-27T21:11:26-03:00
N=A-Z
n=209-83
n=126
________

p=83
______
e=83