Question

Naturally occurring boron consists of two isotopes whose atomic weight are `10.01 and 11.01 `. The atomic weight of the natural boron is `10.81 `. Calculate the percentage of each isotopes in natural boron.

Answer 1

Correct Answer - `20%`
Average atomic weight
`=(Sigma" Percentage of an isotope"xx"Atomic weight")/(100)`
`rArr 10.81=(10.01x +11.01 (100-x))/(100) implies x=20%`
Therefore, natural boron contains `20% (10.01)` isotope and `80%` other isotope.