Question

What is the value of spin only magnetic moment for $Cu^{2+}$ in BM?

• A. 2.84
• B. 3.87
• C. 1.73
• D. 0.0

Hint:

If $n=1, \mu \approx 1.73$; if $n=2, \mu \approx 2.84$; if $n=3, \mu \approx 3.87$.

Answer 1

The Correct Option is C

Step 1: Concept
Magnetic moment ($\mu$) depends on the number of unpaired electrons ($n$).

Step 2: Formula
$\mu = \sqrt{n(n+2)}$ BM

Step 3: Analysis
- $Cu$ ($Z=29$) is $[Ar] 3d^{10} 4s^1$. - $Cu^{2+}$ is $[Ar] 3d^9$. - $d^9$ configuration has 1 unpaired electron ($n=1$). - $\mu = \sqrt{1(1+2)} = \sqrt{3} \approx 1.73$ BM.

Step 4: Conclusion
Hence, the spin-only magnetic moment is 1.73 BM. Final Answer: (C)