Final answer:
The correct formula for Copper (I) Cyanide is CuCN, balancing the 1+ charge of the cuprous ion with the 1- charge of the cyanide ion.
Step-by-step explanation:
The correct formula for Copper (I) Cyanide is CuCN. The copper(I) ion, also known as the cuprous ion, carries a 1+ charge. Cyanide is a one-minus charge ion (CN-). When combining the two to form an ionic compound, they must be charge balanced. Since Copper (I) and Cyanide both have a single charge but opposite in sign (1+ for Copper (I) and 1- for Cyanide), they combine in a 1:1 ratio without the need for subscripts to balance charges.