What are the oxidation states of copper?

Oxidation state:

• The oxidation state is the count of electrons of atoms in a molecule that are shared/lost during the formation of chemical bonds with other elements.
• It is the hypothetical charge of an atom if all of its bonds are fully ionic.

Oxidation states of Copper:

• Copper exists in two oxidation states$+1\mathrm{and}+2$.
• Copper has $9$ electrons in its d orbital; $4$are paired while $1$ remaining unpaired. Thus copper will gain electrons from s orbital in order to attain a stable electronic configuration.
• The $+1$ oxidation state of Copper is known as “Cuprous” while the $+2$ oxidation state is known as “Cupric”.
• An example of Copper in $+1$oxidation state is Cuprous chloride$\left(\mathrm{CuCl}\right)$.
• An example of Copper in $+2$ oxidation state is Cupric chloride $\left({\mathrm{CuCl}}_2\right)$.