Chapter 5 - Electrons in Atoms - 5.2 Electron Arrangement in Atoms - 5.2 Lesson Check - Page 137: 10

The Aufbau Principle states that the lowest energy levels must be filled before the higher ones. The Pauli Exclusion Principle states that each level of energy can hold 2 electrons. Hund's rule states that only one electron may be put in an orbital before pairing them up in the case that all the orbitals are full.

The Aufbau Principle states that the lowest energy levels must be filled before the higher ones. The Pauli Exclusion Principle states that each level of energy can hold 2 electrons. Hund's rule states that only one electron may be put in an orbital before pairing them up in the case that all the orbitals are full.