Match the metal ions given in Column I with the spin magnetic moments of the ions given in Column II and assign the correct code.

The Fundamental Idea The magnetic moment of spin can be calculated as 

$\mathrm{\mu }=\sqrt{\mathrm{n}(\mathrm{n}+2)}\mathrm{BM}$

were,$\mu =\mathrm{Magnetic} \mathrm{moment}$

$\mathrm{BM}=\mathrm{Bohr} \mathrm{Magneton} (\mathrm{unit} \mathrm{of} \mathrm{\mu })$

$\mathrm{n}=\mathrm{Number} \mathrm{of} \mathrm{upaired} \mathrm{electrons} \left({\mathrm{e}}^{-}\right) \mathrm{in} \mathrm{d}-\mathrm{orbital}.$

The electronic arrangement of  ${\mathrm{CO}}^{3+}\text{ is }\left[\mathrm{Ar}\right]3{\mathrm{d}}^6$

Here, n = 4

$\mathrm{\mu }=\sqrt{4(4+2)}+\sqrt{24}\mathrm{BM}$

The electronic arrangement of ${\mathrm{Cr}}^{3+}\text{ is }\left[\mathrm{Ar}\right]3{\mathrm{d}}^3$

Here, n = 3

$\mathrm{\mu }=\sqrt{3(3+2)}=\sqrt{15}\mathrm{BM}$

The electronic arrangement of  ${\mathrm{Fe}}^{3+}\text{ is }\left[\mathrm{Ar}\right]3{\mathrm{d}}^5$

Here, n = 5

$\mathrm{\mu }=\sqrt{5(5+2)}=\sqrt{35}\mathrm{BM}$

The electronic arrangement of ${\mathrm{Ni}}^{2+}\text{ is }\left[\mathrm{Ar}\right]3{\mathrm{d}}^8$

Here, n = 2

$\mathrm{\mu }=\sqrt{2(2+2)}=\sqrt{8}\mathrm{BM}$