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Electron configuration
Intermediate
Filling of shells explains the periodic table.
Electrons fill orbitals in order of increasing energy (1s, 2s, 2p, 3s, 3p, 4s, 3d...) respecting Pauli and Hund's rules. Valence electrons determine chemistry.
Oxygen: 1s²2s²2p⁴.
Exceptions exist (Cr, Cu).
In more detail
Electron configuration describes how electrons fill atomic orbitals, following the Aufbau principle, Pauli exclusion and Hund's rule. It determines the chemical properties of elements.
Real-world uses
- Chemists use electron configurations to predict bonding.
- The periodic table is organised around electron configurations.
- Chemists use electron configurations to predict which elements form ions and how they bond.
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Frequently asked questions
What is the Aufbau principle?
Electrons fill the lowest energy orbitals first.
What is Hund's rule?
Electrons occupy degenerate orbitals singly before pairing.
What is the Aufbau principle?
The rule that electrons fill the lowest available orbitals first before moving to higher ones.
Related topics in Atomic & Nuclear Physics
Continuous X-ray spectrum · Moseley's law · X-ray diffraction · Atomic mass unit · Nucleus composition · Isotopes, isobars, isotones