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1H1.008

Hydrogen

Reactive nonmetalsBlock sPeriod 1Group 1gas at 20 °C
Configuration :
1s¹
Atomic mass :
1.008 u
French :
Hydrogène
3D Bohr-model representation of the Hydrogen atom (symbol H, atomic number Z=1). Electron shell configuration: 1 electrons.
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Bohr model · educational
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Electron configuration

Full1s¹
Short1s¹
Valence electrons1
KLMNOPQ shells
K1

Electronegativity

Pauling2.2
Allen2.3
Mulliken (eV)

Atomic radii

Empirical25 pm
Calculated53 pm
Covalent31 pm
Van der Waals120 pm

Successive ionisation energies

I₁1312 kJ/mol
Electron affinity72.8 kJ/mol

Oxidation states

-1+1
Bold states = most common.
Period 1Block sIUPAC Group 1Family Reactive nonmetals
Sources : NIST Atomic Weights & Isotopic Compositions, IUPAC Recommendations, CODATA. Methodology