Which of the following electronic configuration is not possible according to Hund's rule.

Options

A. `1 s^2 2 s^2`
B. `1 s^2 2 s^1`
C. `1 s^2 2s^2 2 p_x^1 2 p_y^1 2 p_x^1`
D. `1 s^2 2 s^2 2 p_x^2`

Answer

D

Explanation

(d) According to Hund's rule, electron first fills in unpaired form in vacant orbital and then fill in paired form to stabilize the molecule by which `1 s62, 2 s^2, 2 p^2 x` is not possible. According to Hund's rule, because `2p_x, p_y, p_z` have the same energy level so electron first fills in unpaired form, not in paired form so it should be `1 s^2, 2 s^2, 2 p^(1)._(x), 2 p^(1)._(y)`.