Question

How would you compare the abundance of the two naturally occurring isotopes of boron?

Answer 1

By the atomic mass quoted on the Periodic Table.......

Explanation:

The Periodic Table lists the atomic mass of boron as `10.81*g*mol^-1`. This site informs me that the percentage occurrence of `""^(10)B` is `19.9%`, and of `""^(11)B`, `80.1%`.

These are the only significant isotopes of boron, and their weighted average is:

`(10xx19.9%+11xx80.1%)*g*mol^-1` `=` `10.81*g*mol^-1`

And thus, when you look on your copy of the Periodic Table, you find this molar mass quoted.