N the ionic compound aluminum selenide, each atom of aluminum (gains or loses) (number)
electron(s) while each atom of selenium (gains or loses)
(number)
electron(s).

loses, gains

Explanation:

In the ionic compound aluminum selenide, each atom of aluminum will lose electrons while each atom of selenium will gain the electrons.

An ionic compound is an interatomic bond formed between a metal and non-metal. The metal is less electronegative compared to the non-metal. In this case, the metal will lose electrons to become positively charged whereas the non-metal, selenium will gain the electron to become negatively charged.

The electrostatic attraction between these oppositely charged ions leads to the formation of the ionic bond.