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

Options

A. `1s^(2)2s^(2)`
B. `1s^(2)2s^(1)`
C. `1s^(2)2s^(2)2p_(x)^(1)2p_(y)^(1)2p_(z)^(1)`
D. `1s^(2)2s^(2)2p_(x)^(2)`

Answer

D

Explanation

According to Hund.s rule electron first fill in unpaired form in vacant orbital then fill in paired form to stabilize the molecule by which `1s^(2),2s^(2),2p_(x)^(2)` is not possible. According to Hund.s rule. Because `2p_(x),p_(y),p_(z)` have the same energy level so electron first fill in unpaired form not in paired form so it should be `1s^(2),2s^(2),2p_(x)^(1),2p_(y)^(1)`.