18Ar39.95

Argon

Noble gasesBlock pPeriod 3Group 18gas at 20 °C
Configuration :[Ne] 3s² 3p⁶
Atomic mass :39.95 u
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Modèle de Bohr · pédagogique

Electron configuration

Full1s² 2s² 2p⁶ 3s² 3p⁶
Short[Ne] 3s² 3p⁶
Valence electrons8
KLMNOPQ shells
K2
L8
M8

Electronegativity

Pauling
Allen3.242
Mulliken (eV)

Atomic radii

Empirical71 pm
Calculated71 pm
Covalent106 pm
Van der Waals188 pm

Successive ionisation energies

I₁1520.6 kJ/mol
I₂2665.8 kJ/mol
I₃3931 kJ/mol
I₄5771 kJ/mol
I₅7238 kJ/mol
Electron affinity

Oxidation states

0
Bold states = most common.
Period 3Block pIUPAC Group 18Family Noble gases
Sources : NIST Atomic Weights & Isotopic Compositions, IUPAC Recommendations, CODATA. Methodology