Question #a31cd

1 Answer
Aug 14, 2016

Those are mass numbers of each molecular isotope, meaning those of Br2. Bromine is naturally a diatomic liquid.

It doesn't mean that there are three naturally-existing atomic isotopes, but it does mean that one Br on Br2 doesn't necessarily have to be 8135Br if the other is 8135Br, for example.

Add up the mass numbers and you should see that:

79+79=158
79+81=160
81+81=162

That means you have the three naturally-existing isotopic molecules:

7935Br7935Br

7935Br8135Br

8135Br8135Br

Therefore, you still have:

  • Two naturally-existing atomic isotopes.
  • Due to the diatomic nature of naturally-existing bromine liquid, three combinations of atoms are possible, generating three naturally-existing molecules containing the three different combinations of atomic isotopes.