Question

Which of the following electronic configurations are associated with the formation of a molecule with expanded octet?

• A. $\left[He\right]2s^{2}2p^1$
• B. $\left[He\right]2s^{2}2p^2$
• C. $\left[Ne\right]3s^{2}3p^3$
• D. $\left[Ne\right]3s^{2}3p^4$

Answer 1

Answer: (C), (D)

The correct options are
C $\left[Ne\right]3s^{2}3p^3$
D $\left[Ne\right]3s^{2}3p^4$

The electronic configurations $\left[Ne\right]3s^{2}3p^3$ and $\left[Ne\right]3s^{2}3p^4$ are associated with the formation of molecule with expanded octet. In these electronic configurations electrons can be excited from $3p$ subshell to $3d$ subshell. Elements belonging to second period of the periodic table do not form such stable molecules as they do not have d orbitals.