What would the charge be on an ion of boron (b)?

3+

Explanation:

Boron belongs to the 3rd group, the Boron family on the periodic table. It has an atomic number of 5. For neutral atoms of Boron, we have 5 electrons in them.

All atoms lose or gain electrons in order to achieve a perfect noble gas configuration which would give them stability. Noble gases are known to be stable and unreactive.

For Boron, it would readily want to lose 3 electrons so as to mimic a Helium, He atom. Helium is the first element in the noble gas series.

When Boron loses 3 electrons, a net charge of 3+ is left on the atom of Boron.