The calculated magnetic moment of Cu²⁺ ion is 

Electronic configuration of Cu(29) =[Ar]3d¹⁰4s¹

Electronic configuration of Cu²⁺:[Ar] 3d⁹4s⁰. It has only one unpaired electron. So, magnetic moment is calculated as:

$$\begin{gathered} \mu =\sqrt{\mathrm{n}(\mathrm{n}+2)} \\ =\sqrt{1(1+2)} \\ =\sqrt{3 } \\ =1.732 \end{gathered}$$