Final answer:
The formula for Copper (II) nitride is Cu²⁺N³⁻.
Step-by-step explanation:
The formula for Copper (II) nitride is Cu2+N3-. The Roman numeral (II) in the name indicates the charge on the copper ion, which is +2. The nitride ion, N3-, has a charge of -3. To balance the charges, one copper ion with a charge of +2 combines with three nitride ions, each with a charge of -1, resulting in the formula CuN3.