Question

Which rule is violated in the electronic configuration 1s0 2s2 2p4

Answer 1

Aufbau principle is being violated here

Answer 2

aufbauprinzip or aufbau principle. this principle states that orbitals in the lowest energy level must first be filled up before going to the higher level orbitals. the first that should be filled up is 1s. So it should be 1s2 2s2 2p2 which is actually carbon :)