Question

Which of the following ions having the following electronic structure would have a maximum magnetic moment?

• A. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^3$
• B. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^5$
• C. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^7$
• D. $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^9$

Answer 1

Answer: (B)

$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^5$

Magnetic moment = $\sqrt{n(n+2)}$, where n is no. of unpaired electrons.

Higher the number of unpaired electrons, higher is the magnetic moment.

Number of unpaired electrons are maximum in option B (5 unpaired electrons).

Option A and C: 3 unpaired electrons.

Option D: 1 unpaired electron.