Question

what happens when a strontium atom loses 2 valence electrons? what does it become and what charge will it be?

Answer 1

It becomes a strontium ion (positive ion, cation) Sr2+ in the same way that Magnesium losing two valence electrons becomes Mg2+

Answer 2

This is because initially the number of protons with a positive charge and electrons with a negative charge was the same in the atom, but then two electrons with a negative charge were taken away, hence now there is more positive charge