What is the chemical formula for copper oxide?

What is the chemical formula for copper oxide?

• A. CuO
• B. Cu2O
• C. CuO2
• D. Cu

Answer: (A)

Oxides are compounds that contain oxide ions (O^2−). To make a neutral compound with copper, the charges must balance. Copper can form +2 or +1 ions. When copper is in the +2 state, it pairs with one oxide ion in a 1:1 ratio, giving CuO. This is copper(II) oxide, a common form of copper oxide, and it has the correct overall neutral charge. There is another oxide of copper, Cu2O, which contains copper in the +1 state (copper(I) oxide); it’s a different compound with a different ratio of copper to oxygen. CuO2 would not balance to a neutral compound under simple ionic rules, and copper in metallic form is not an oxide. So CuO is the best match for copper oxide in this context, representing copper in the +2 state with one oxide ion to balance charges.

Oxides are compounds that contain oxide ions (O^2−). To make a neutral compound with copper, the charges must balance. Copper can form +2 or +1 ions. When copper is in the +2 state, it pairs with one oxide ion in a 1:1 ratio, giving CuO. This is copper(II) oxide, a common form of copper oxide, and it has the correct overall neutral charge.

There is another oxide of copper, Cu2O, which contains copper in the +1 state (copper(I) oxide); it’s a different compound with a different ratio of copper to oxygen. CuO2 would not balance to a neutral compound under simple ionic rules, and copper in metallic form is not an oxide.

So CuO is the best match for copper oxide in this context, representing copper in the +2 state with one oxide ion to balance charges.