Q. According to aufbau principle, the correct order of energy of $3d,\ 4s\$and $4p$-orbitals is
A) $4p < 3d < 4s$
B) $4s < 4p < 3d$
C) $4s < 3d < 4p$
D) $3d < 4s < 4p$
Explanation
(c)
According to aufbau principle, as electron enters the orbital of lowest energy first and subsequent electrons are fed in the order of increasing energies. The relative energies of various orbital in increasing order are
$1s,2s,2p,3s,3p,4s,3d,4p,5s,4d,5p,6s,4f,5d,6p,7s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.