Question

What is the value of spin only magnetic moment for \(\text{Cu}^{2+}\) in BM?

• A. \(2.84\)
• B. \(3.87\)
• C. \(1.73\)
• D. \(0.0\)

Hint:

Find unpaired electrons in d9 and use sqrt(n(n+2)).

Answer 1

The Correct Option is C

Step 1: Count:
Cu$^{2+}$ is $d^9$. Ten spaces in five $d$ orbitals, nine electrons, so exactly one is unpaired.

Step 2: Use the formula:
$\mu = \sqrt{n(n+2)}$ with $n=1$ gives $\sqrt{3}$.

Step 3: Value:
$\sqrt{3} = 1.732$, option (C).

Final Answer:
sqrt(3) = 1.73 BM for one unpaired electron. \[ \boxed{C} \]