The formula unit for the ionic compound, magnesium sulfide, consists of which of the following?

Question

? 2 Mg+ ions and 1 S2- ion
? 1 Mg+ ion and 1 S- ion
? 1 Mg2- ion and 1 S2+ ion
? 1 Mg2+ ion and 1 S2- ion
? 1 Mg2+ ion and 2 S- ions

Answer 1

The correct formula unit for the ionic compound magnesium sulfide is 1 Mg2+ ion and 1 S2- ion.

In magnesium sulfide (MgS), each magnesium ion (Mg2+) has a charge of +2, and each sulfide ion (S2-) has a charge of -2. The charges balance out to form a neutral compound, which is consistent with the formula unit MgS. Therefore, the answer is:

1 Mg2+ ion and 1 S2- ion.