Match the metal ions given in Column 'I' with the spin magnetic moments of the ions given in Column 'II'. Column I Column II a. ${\mathrm{Co}}^{3+}$ i. $\sqrt{8} B.M.$ b. ${\mathrm{Cr}}^{3+}$ ii. $\sqrt{35} B.M.$ c. ${\mathrm{Fe}}^{3+}$ iii. $\sqrt{3} B.M.$ d. ${\mathrm{Ni}}^{2+}$ iv. $\sqrt{24} B.M.$ v. $\sqrt{15}B.M$

Magnetic moment $(\mu )=\sqrt{n(n+2)} B.M.$ (i) ${\mathrm{Co}}^{3+}\rightarrow 1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}4{s}^{0}3{d}^{6}$ ![NEET 2018 Chemistry, d and f Block Elements — solution figure 1](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/616059730283de43c87e3e22/Chemistry/images/d_and_f_Block_Elements/66bcbfacae81d148616b2335/solution_1__q_66bcbfacae81d148616b2335__cdn-question-pool.getmarks.app__7bcc3638-a065-4253-9796-d301efc05ffc-image__b75780f6bd_final_ppt_sync.png) $n=4$ $\mu = \sqrt{4(4+2)}=\sqrt{24} B.M.$ (ii) ${\mathrm{Cr}}^{+3}\rightarrow 1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}4{s}^{0}3{d}^{3}$ ![NEET 2018 Chemistry, d and f Block Elements — solution figure 2](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/616059730283de43c87e3e22/Chemistry/images/d_and_f_Block_Elements/66bcbfacae81d148616b2335/solution_2__q_66bcbfacae81d148616b2335__cdn-question-pool.getmarks.app__c9e3700d-c10f-4265-b7fe-32654f17c0a2-image__9625c184ec_final_ppt_sync.png) $n=3$ $\mu = \sqrt{3(3+2)}= \sqrt{15} B.M.$ (iii) ${\mathrm{Fe}}^{3+}\rightarrow 1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}4{s}^{0}3{d}^{5}$ ![NEET 2018 Chemistry, d and f Block Elements — solution figure 3](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/616059730283de43c87e3e22/Chemistry/images/d_and_f_Block_Elements/66bcbfacae81d148616b2335/solution_3__q_66bcbfacae81d148616b2335__cdn-question-pool.getmarks.app__fcb2d1bb-a316-440c-bc93-593f2c0b2c0e-image__0d08ee40fb_final_ppt_sync.png) $n=5$ $\mu = \sqrt{5(5+2)}= \sqrt{35} B.M.$ (iv) ${\mathrm{Ni}}^{+2}\rightarrow 1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}4{s}^{0}3{d}^{8}$ ![NEET 2018 Chemistry, d and f Block Elements — solution figure 4](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/616059730283de43c87e3e22/Chemistry/images/d_and_f_Block_Elements/66bcbfacae81d148616b2335/solution_4__q_66bcbfacae81d148616b2335__cdn-question-pool.getmarks.app__c08d61aa-732c-4ec7-8392-49913c6b3da2-image__c88057ac59_final_ppt_sync.png) $n=2$ $\mu = \sqrt{2(2+2)}= \sqrt{8} B.M.$

NEET UG 2018 — Chemistry Inorganic Chemistry

2018mcqhard

Match the metal ions given in Column 'I' with the spin magnetic moments of the ions given in Column 'II'.

Column I	Column II
a. ${\mathrm{Co}}^{3+}$	i. $\sqrt{8} B.M.$
b. ${\mathrm{Cr}}^{3+}$	ii. $\sqrt{35} B.M.$
c. ${\mathrm{Fe}}^{3+}$	iii. $\sqrt{3} B.M.$
d. ${\mathrm{Ni}}^{2+}$	iv. $\sqrt{24} B.M.$
	v. $\sqrt{15}B.M$

Official previous-year question

Held on 30 Apr 2018 · Verified 9 Jul 2026.

Options

A
$\begin{matrix}a & b & c \\ iv & i & ii\end{matrix} \begin{matrix}d \\ iii\end{matrix}$
B
$\begin{matrix}a & b & c \\ iii & v & i\end{matrix} \begin{matrix}d \\ ii\end{matrix}$
C
$\begin{matrix}a & b & c \\ i & ii & iii\end{matrix} \begin{matrix}d \\ iv\end{matrix}$
D
$\begin{matrix}a & b & c \\ iv & v & ii\end{matrix} \begin{matrix}d \\ i\end{matrix}$

Did you get this right?

Solution

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

(i) ${\mathrm{Co}}^{3+}\rightarrow 1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}4{s}^{0}3{d}^{6}$

NEET 2018 Chemistry, d and f Block Elements — solution figure 1

$n=4$

$\mu = \sqrt{4(4+2)}=\sqrt{24} B.M.$

(ii) ${\mathrm{Cr}}^{+3}\rightarrow 1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}4{s}^{0}3{d}^{3}$

NEET 2018 Chemistry, d and f Block Elements — solution figure 2

$n=3$

$\mu = \sqrt{3(3+2)}= \sqrt{15} B.M.$

(iii) ${\mathrm{Fe}}^{3+}\rightarrow 1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}4{s}^{0}3{d}^{5}$

NEET 2018 Chemistry, d and f Block Elements — solution figure 3

$n=5$

$\mu = \sqrt{5(5+2)}= \sqrt{35} B.M.$

(iv) ${\mathrm{Ni}}^{+2}\rightarrow 1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}4{s}^{0}3{d}^{8}$

NEET 2018 Chemistry, d and f Block Elements — solution figure 4

$n=2$

$\mu = \sqrt{2(2+2)}= \sqrt{8} B.M.$

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Options

$\begin{matrix}a & b & c \\ iv & i & ii\end{matrix} \begin{matrix}d \\ iii\end{matrix}$

$\begin{matrix}a & b & c \\ iii & v & i\end{matrix} \begin{matrix}d \\ ii\end{matrix}$

$\begin{matrix}a & b & c \\ i & ii & iii\end{matrix} \begin{matrix}d \\ iv\end{matrix}$

$\begin{matrix}a & b & c \\ iv & v & ii\end{matrix} \begin{matrix}d \\ i\end{matrix}$

Solution

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

(i) ${\mathrm{Co}}^{3+}\rightarrow 1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}4{s}^{0}3{d}^{6}$

NEET 2018 Chemistry, d and f Block Elements — solution figure 1

$n=4$

$\mu = \sqrt{4(4+2)}=\sqrt{24} B.M.$

(ii) ${\mathrm{Cr}}^{+3}\rightarrow 1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}4{s}^{0}3{d}^{3}$

NEET 2018 Chemistry, d and f Block Elements — solution figure 2

$n=3$

$\mu = \sqrt{3(3+2)}= \sqrt{15} B.M.$

(iii) ${\mathrm{Fe}}^{3+}\rightarrow 1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}4{s}^{0}3{d}^{5}$

NEET 2018 Chemistry, d and f Block Elements — solution figure 3

$n=5$

$\mu = \sqrt{5(5+2)}= \sqrt{35} B.M.$

(iv) ${\mathrm{Ni}}^{+2}\rightarrow 1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}4{s}^{0}3{d}^{8}$

NEET 2018 Chemistry, d and f Block Elements — solution figure 4

$n=2$

$\mu = \sqrt{2(2+2)}= \sqrt{8} B.M.$

NEET UG 2018 — Chemistry Inorganic Chemistry

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Solution

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Solution

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