Question

Which one of the following has maximum number of unpaired electrons?

• A. \( \text{Mg}^{2+} \)
• B. \( \text{Fe}^{3+} \)
• C. \( \text{Ti}^{3+} \)
• D. \( \text{F}^{-} \)

Hint:

The number of unpaired electrons can be determined by the electron configuration of the ion. Look at the last sublevel to identify unpaired electrons.

Answer 1

The Correct Option is D

Step 1: Electron configuration and unpaired electrons. The number of unpaired electrons can be determined from the electron configuration of the ions. - \( \text{Mg}^{2+} \): \( 1s^2 2s^2 2p^6 \) (no unpaired electrons). - \( \text{Fe}^{3+} \): \( [Ar] 3d^5 \) (5 unpaired electrons). - \( \text{Ti}^{3+} \): \( [Ar] 3d^1 \) (1 unpaired electron). - \( \text{F}^{-} \): \( [He] 2s^2 2p^6 \) (no unpaired electrons).
Step 2: Conclusion. Thus, \( \text{Fe}^{3+} \) has the maximum number of unpaired electrons (5).