Question

Which rule is violated in the electronic configuration $1s^{0}2s^{2}2p^4$?

Answer 1

Aufbau Principle is violated as the orbital having lower energy must be filled first. So $1s$ could not be vacant in $1s^{0}2s^{2}2p^4$.

An electron having the lowest value of $(n+l)$ will be filled first.