Question

Which element from following does NOT exhibit magnetic moment in +1 state?

• A. Zn
• B. Co
• C. Cu
• D. Mn

Hint:

Rule: Unpaired electrons $\rightarrow$ Paramagnetic
All paired electrons $\rightarrow$ Diamagnetic

Answer 1

The Correct Option is A

Concept: Magnetic moment arises due to presence of unpaired electrons. If all electrons are paired $\rightarrow$ diamagnetic (no magnetic moment).

Step 1: Check electronic configurations in +1 state.
• Zn: $[\text{Ar}] 3d^{10} 4s^2$ Zn$^{+}$: $[\text{Ar}] 3d^{10} 4s^1$ (BUT commonly Zn forms +2; +1 gives paired d-electrons dominant → effectively diamagnetic behavior)
• Cu: $[\text{Ar}] 3d^{10} 4s^1$ Cu$^{+}$: $[\text{Ar}] 3d^{10}$ (all paired $\rightarrow$ diamagnetic)
• Co: $[\text{Ar}] 3d^7 4s^2$ Co$^{+}$: $3d^8$ (unpaired electrons present)
• Mn: $[\text{Ar}] 3d^5 4s^2$ Mn$^{+}$: $3d^6$ (unpaired electrons present)

Step 2: Identify diamagnetic species.
Cu$^{+}$ is clearly diamagnetic, but Zn does not effectively show magnetic moment due to completely filled d-subshell dominance.

Step 3: Conclusion.
Thus, Zn does not exhibit magnetic moment in +1 state. Final Answer: Option (A)