Question

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 :
$\begin{array}{cccc}& \text{Column-I}& & \text{Column-II}\\ a.& C{o}^{3+}& i.& \sqrt{8}BM\\ b.& C{r}^{3+}& ii.& \sqrt{35}BM\\ c.& F{e}^{3+}& iii.& \sqrt{3}BM\\ d.& N{i}^{2+}& iv.& \sqrt{24}BM\\ & & v.& \sqrt{15}BM\end{array}$

• A. a-iv, b-i,c-ii,d-iii
• B. a-i, b-ii, c-iii, d-iv
• C. a-iv, b-v, c-ii, d-i
• D. a-iii, b-v, c-i, d-ii

Answer 1

The correct option is C a-iv, b-v, c-ii, d-i

$C{o}^{3+}=\left[Ar\right]3d^6$, unpaired $e^{-}$ (n) = 4
Spin magnetic moment $=\sqrt{4(4+2)}=\sqrt{24}BM$
$C{r}^{3+}=\left[Ar\right]3d^3$, unpaired $e^{-}\left(n\right)=3$
Spin magnetic moment $=\sqrt{3(3+2)}=\sqrt{15}BM$
$F{e}^{3+}=\left[Ar\right]3d^5$, unpaired $e^{-}\left(n\right)=5$
Spin magnetic moment $=\sqrt{5(5+2)}=\sqrt{35}BM$
$N{i}^{2+}=\left[Ar\right]3d^8$, unpaired $e^{-}\left(n\right)=2$
Spin magnetic moment $=\sqrt{2(2+2)}=\sqrt{8}BM$