Question

copper + oxygen = cupric oxide

Answer 1

it depends upon the valency of copper

if the valency is 2 then cuprous oxide

and if the valency is 3 it is cupric oxide

Answer 2

Answer:

When Copper (Cu) is heated , the  oxygen from the air combines with copper to form copper(II) oxide.

The colour of copper changes to black .

Therefore,

the coating formed on the surface of copper is copper oxide or cupric oxide (CuO).

Here is the chemical equation for the chemical reaction :-

                      heat

2Cu + O₂   --------------> 2CuO

This is also an example of oxidation .

Copper is the getting oxidised to CuO.