What is the formula for copper(II) sulfide?

To determine the correct formula for copper(II) sulfide, we first need to understand the components involved. Copper(II) indicates that copper has a +2 oxidation state, meaning it will lose two electrons. Sulfide refers to sulfur in a -2 oxidation state.

When forming the compound, the total positive charge from the copper needs to balance the total negative charge from the sulfide. Since copper is in the +2 oxidation state, one copper atom will pair with one sulfur atom (which has a -2 charge) to achieve electrical neutrality.

Thus, the formula for copper(II) sulfide is CuS, indicating one copper atom and one sulfur atom together. This formula effectively represents the combination of the oxidation states, ensuring that the charges add up to zero.

Other options do not accurately reflect the oxidation states or the correct ionic ratio needed to form copper(II) sulfide, which confirms that CuS is indeed the correct answer.