https://study.com/academy/lesson/atomic-structures-pauli-exclusion-principle-aufbau-principle-hundsrule.html
Pauli Exclusion Principle
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supple
mental_Modules_(Physical_and_Theoretical_Chemistry)/Electronic_Structure_of_Atoms_and_Molecule
s/Electronic_Configurations/Pauli_Exclusion_Principle
http://hyperphysics.phy-astr.gsu.edu/hbase/pauli.html
Hunds Rules
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supple
mental_Modules_(Physical_and_Theoretical_Chemistry)/Electronic_Structure_of_Atoms_and_Molecule
s/Electronic_Configurations/Hund's_Rules
Aufbau Principle
https://byjus.com/chemistry/aufbau-principle/
octet rule
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supple
mental_Modules_(Physical_and_Theoretical_Chemistry)/Electronic_Structure_of_Atoms_and_Molecule
s/Electronic_Configurations/The_Octet_Rule
Quantum Theory
https://blogs.scientificamerican.com/observations/what-does-quantum-theory-actually-tell-us-aboutreality/