Aufbau's Principle, Hund's Rule & Pauli's Exclusion Principle - Electron Configuration - Chemistry

Aufbau's Principle states that electrons fill the lowest energy levels first. Hund's Rule indicates that electrons occupy degenerate orbitals singly with parallel spins before pairing. Pauli's Exclusion Principle asserts that no two electrons can share the same set of four quantum numbers, ensuring each electron's unique identity within an atom.