Key Concepts: Electron Configuration

Core Definitions

• Electron Configuration: The arrangement of electrons in an atom's orbitals (e.g., 1s² 2s² 2p⁶).
• Aufbau Principle: Electrons fill orbitals from lowest to highest energy.
• Pauli Exclusion Principle: Each orbital can hold a maximum of 2 electrons with opposite spins.
• Hund's Rule: Electrons fill orbitals of the same sublevel singly before pairing up.
• Noble Gas Shorthand: Uses the preceding noble gas symbol in brackets to abbreviate (e.g., [Ne] 3s² 3p³ for phosphorus).
• Diagonal Rule: The filling order follows a diagonal pattern: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p...