How many ion does the element boron has?

Boron's atomic number is 5, so for its 5 protons, it should have 5 electrons if it's neutral.

To make it an ion, Boron's charge would have to be negative or positive. It could lose one electron to have a charge of +1, gain an electron to be -1 ion.

Ions aren't at specific number. So the answer depends on Boron's tendency to gain or lose electrons.