According to the Aufbau principle,which of the following subshells is typically filled next after the 4s subshell?
A) 3d
B) 4s
C) 3p
D) 2p
E) 2s

Question

Quizplus · Accepted Answer

According to the Aufbau principle, the subshells are filled in increasing order of their energies. Even though the 3d subshell has a higher energy than the 4s subshell initially, it becomes lower in energy when electrons start occupying it. Therefore, after filling the 4s subshell, the next subshell that is typically filled is the 3d subshell.

According to the Aufbau Principle,which of the Following Subshells Is