What is the numerical value of spin only magnetic moment of copper in +2 state?

What is the numerical value of spin only magnetic moment of copper in +2 state?
  1. 0.0
  2. 1.73
  3. 2.78
  4. 4.4

Solution

$\begin{aligned} & \mathrm{Cu}(\mathrm{Z}=29):[\mathrm{Ar}] 3 \mathrm{~d}^{10} 4 \mathrm{~s}^1 \\ & \mathrm{Cu}^{2+}:[\mathrm{Ar}] 3 \mathrm{~d}^9 \\ & \text { No. of unpaired } \mathrm{e}^{-}=1 \\ & \mu=\sqrt{\mathrm{n}(\mathrm{n}+2)}=\sqrt{1(1+2)}=\sqrt{3}=1.73 \mathrm{BM}\end{aligned}$

Asked in: MHT CET 2023 (12 May Shift 1)

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