Question

Which of the following ions has the least magnetic moment.

• A. $Cu^{+ 2}$
• B. $Ni^{+ 2}$
• C. $Co^{+ 3}$
• D. $Fe^{+ 2}$

Answer 1

Answer: (A)

$Cu^{+ 2}$

Answer 2

$Cu^{+ 2}$

S.N	Ion	Electronic Configuration	No. of unpaired electrons
(i)	Cu+2	d9	1
(ii)	Ni+2	d8	2
(iii)	Co+2	d7	3
(iv)	Fe+2	d6	4

$\mu = \sqrt{n(n + 2)}$ (magnetic moment)

$\mu \propto \sqrt{n}$

$Cu^{+ 2}$ there is only 1 unpaired electron so its magnetic moment is least.