Question

The aufbau principle, from the German Aufbauprinzip, also called the aufbau rule​

Answer 1

Answer:

The aufbau principle, from the German Aufbauprinzip (building-up principle), also called the aufbau rule, states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels.

Explanation:

Proposed by the Danish physicist Niels Bohr in the early 1920s, the principle was a tool for obtaining a picture of the atomic constitution, i.e., the arrangement of electrons on orbits around the nucleus.