Chapter 12, Problem 5STP

Interpretation Introduction

Interpretation:

The ion that doesn’t have noble gas configuration is to be chosen.

Concept introduction:

The electronic configuration in which octet is complete is referred as noble gas configuration.

Answer to Problem 5STP

D

Explanation of Solution

Electronic configuration of $N{a}^{+}$ :

  $1s^{2}2s^{2}2p^6$

Electronic configuration of $M{g}^{2+}$ :

  $1s^{2}2s^{2}2p^6$

Electronic configuration of $S^{2-}$ :

  $1s^{2}2s^{2}2p^{6}3s^{2}3p^6$

Electronic configuration of $F{e}^{3+}$:

  $\left[Ar\right]3d^5$

The octet of $F{e}^{3+}$ is not complete. So it doen’t have noble gas configuration.

Conclusion

Options A, B and C are wrong because all the three ions have noble gas configuration.