Question

The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.

• A. \(3d^7\)
• B. \(3d^5\)
• C. \(3d^8\)
• D. \(3d^2\)

Hint:

Greater the number of unpaired electrons: \[ \Rightarrow \] greater the magnetic moment.

Answer 1

The Correct Option is B

Step 1: Recall the formula for magnetic moment.
Magnetic moment depends on number of unpaired electrons: \[ \mu=\sqrt{n(n+2)}\ \mathrm{BM} \] where: \[ n=\text{number of unpaired electrons} \]

Step 2: Find unpaired electrons in each configuration.
\[ 3d^7 \Rightarrow 3\ \text{unpaired electrons} \] \[ 3d^5 \Rightarrow 5\ \text{unpaired electrons} \] \[ 3d^8 \Rightarrow 2\ \text{unpaired electrons} \] \[ 3d^2 \Rightarrow 2\ \text{unpaired electrons} \]

Step 3: Identify highest magnetic moment.
Maximum magnetic moment corresponds to maximum number of unpaired electrons. Thus: \[ 3d^5 \] has highest magnetic moment.

Step 4: Identify the correct option.
Therefore: \[ \boxed{ \mathrm{ (B)\ 3d^5 } } \]