Question

What is the valency of Cu in CuO and Cu2O?

Answer 1

Cu valency in CuO is 2+
and in Cu2O is 1+

Answer 2

Copper is an element which can show two different valencies ,i.e., +1 & +2.
So,
In CuO , the valency of Cu is +2.
In Cu2O , the valency of Cu is +1.