Question

The spin only magnetic moment of a divalent ion in aqueous solution (atomic number 29) is (nearest integer)

JEE MAINS 2021

Answer 1

The element having atomic no. 29 is copper
The electronic configuration of $C{u}^{2+}$ is
$C{u}^{2+}$ : $\left[Ar\right]3d^9$

It has 1 unpaired electron


$\mu =\sqrt{\left(n\right(n+2)}=\sqrt{3}=1.73BM=2\left(nearestinteger\right)$