Chemistry help- naming compounds, Why does CuO = Copper II Oxide?
The valence or oxidation number of one oxygen atom found in CuO is always -2, and the overall charge on any chemical compound is always zero. So what number can you add to a -2 to make it a zero. Got to be a plus 2, so that is why CuO is copperII oxide. If you saw, Cu2O, you would know that oxygen has a – 2 charge, the whole compound Cu2O is neutral, so both Cu atoms together must have a total charge of +2, and each Cu atom must be a + 1 so we call this compound, Copper I oxide, old name was Cuprous oxide, and the old name for Copper II oxide was Cupric oxide.