The formula unit for the ionic compound, copper(I) sulfide, consists of which of the following?

Question

? 1 Cu2+ ion and 1 S2- ion
? 2 Cu+ ions and 1 S2- ion
? 1 Cu2+ ion and 2 S- ions
? 1 Cu+ ion and 1 S- ion
? 2 Cu- ions and 1 S2+ ion

Answer 1

The formula unit for copper(I) sulfide is composed of 2 Cu\(^+\) ions and 1 S\(^2-\) ion.

This is because copper(I) means that copper has a +1 oxidation state, while sulfur in sulfide has a -2 oxidation state. To balance the charge, two Cu\(^+\) ions (totaling +2) pair with one S\(^2-\) ion (totaling -2).

Therefore, the correct option is:

• 2 Cu\(^+\) ions and 1 S\(^2-\) ion.