Find the number of species from the following which has magnetic moment value of 1.73 B.M

${\mathrm{Fe}}^{2+},{\mathrm{Cu}}^{2+},{\mathrm{Ni}}^{2+},{\mathrm{NO}}_2,{\mathrm{NO}}_2^{-},{\mathrm{Sc}}^{2+}$

Electronic configuration of $S{c}^{\mathit{+}\mathit{2}}=1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^1$

$\therefore$Magnetic moment $=\sqrt{n(n+2)}$ B.M.

Where,

n = Number of unpaired elecrons.

$\therefore$ Magnetic momental ${\mathrm{Sc}}^{+2}=\sqrt{1(1+2)}$ B.M.

$$\begin{gathered} =\sqrt{3} \mathrm{B}.\mathrm{M}. \\ =1.732 \mathrm{B}.\mathrm{M}. \end{gathered}$$

The magnetic moment of Cu2+ and No2- is also same.