Q. Which of the following electronic configuration is not possible?
A) $1s^{2},2s^{2}$
B) $1s^{2},2s^{2}2p^{6}$
C) $\lbrack Ar\rbrack 3d^{10},4s^{2}4p^{2}$
D) $1s^{2},2s^{2}2p^{2},3s^{1}$
Explanation
(d)
According to aufbau principle, 2p-orbital will be filled before 3s-orbital. Therefore, the electronic configuration $(1s^{2},2s^{2}2p^{2},3s^{1})$ is not possible.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.