Question

The orbital diagram in which Aufbau principle is violated is

• A.
• B.
• C.
• D.

Answer 1

Answer: (C)

Answer 2

In option $[c]$, Aufbau principle is violated. According to this rule, the orbital with lower value of $n$, i.e., $25$ will be filled first completely.
In option $[a]$ "Hund's rule of maximum multiplicity" is violated. According to this rule, the pairing of electrons in orbitals of a subshell does not take place untill all the orbitals of a subshell are singly occupied.