The term 'valency' is an antiquated term that is no longer used in modern chemistry. Instead, we use the term 'oxidation state'.

Cupric ion: The oxidation state of cupric ion is +2. This means that the copper atom in cupric ion has lost two electrons.

Cuprous ion: The oxidation state of cuprous ion is +1. This means that the copper atom in cuprous ion has lost one electron.