What three principles guide the electron configuration of an atom?

Answer 1

The Aufbau (building up) principle. Hundt's rule (electrons tend to spread themselves out among equivalent orbitals, such as the p's and d's). The Pauli exclusion principle (no two electrons can have all four quantum numbers the same)(English translation: Spins must be different).

The aufbau principle is the familiar 2 in the 1s, then 2 in the 2s, the 6 in the 2p, undsoweiter.

Hundt's rule specifies that in nitrogen, there are 2 in the 1s, 2 in the 2s, and one each in the 2px, 2py, and 2pz. This rule plays a more important part in d-orbitals and the chemistry of the transition metal elements.

And the Pauli exclusion principle is obvious.