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 :

Column I	Column II
$\left(a\right)C{o}^{3+}$	$\left(i\right)\sqrt{8}BM$
$\left(b\right)C{r}^{3+}$	$\left(ii\right)\sqrt{35}BM$
$\left(c\right)F{e}^{3+}$	$\left(iii\right)\sqrt{3}BM$
$\left(d\right)N{i}^{2+}$	$\left(iv\right)\sqrt{24}BM$
	$\left(v\right)\sqrt{15}BM$

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> NEET 2018

• A. $\left(a\right)-iv;\left(b\right)-i;\left(c\right)-ii;\left(d\right)-iii$
• B. $\left(a\right)-iii;\left(b\right)-v;\left(c\right)-i;\left(d\right)-ii$
• C. $\left(a\right)-i;\left(b\right)-ii;\left(c\right)-iii;\left(d\right)-iv$
• D. $\left(a\right)-iv;\left(b\right)-v;\left(c\right)-ii;\left(d\right)-i$

Answer 1

The correct option is D $\left(a\right)-iv;\left(b\right)-v;\left(c\right)-ii;\left(d\right)-i$

$C{o}^{3+}=\left[Ar\right]3d^6$ , unpaired $e^{-}\left(n\right)=4$

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
$=\sqrt{2(2+2)}=\sqrt{8}BM$
Option (a) is correct match