Question

when a formula unit of magnesium sulfide, mgs, is separated into magnesium and sulfur particles, the particles are called

molecules.

ions.

isotopes.

compounds.

Explanation:

Magnesium sulfide (MgS) is an ionic compound formed by the transfer of electrons: magnesium loses 2 electrons to form a positively charged $\text{Mg}^{2+}$ cation, and sulfur gains 2 electrons to form a negatively charged $\text{S}^{2-}$ anion. When separated, the resulting charged particles are ions. Molecules are neutral covalent particles, isotopes are variant forms of the same element, and compounds are pure substances made of multiple elements, so these do not fit.

Answer:

ions.