Hydrogen (H)
Hydrogen (H) is element 1, a nonmetal. Atomic mass 1.008, configuration 1s¹. Properties, isotopes, oxidation states, uses and history, with an interactive 3D atom model.
Key facts
| Atomic number | 1 |
|---|---|
| Symbol | H |
| Standard atomic weight | [1.00784,1.00811] |
| Category | Other nonmetal |
| Group | 1 |
| Period | 1 |
| State at room temperature | Gas |
| Electron configuration | 1s¹ |
| Valence electrons | 1 |
| Common oxidation states | -1, +1 |
| Common ions | H⁻, H⁺ |
| Electronegativity (Pauling) | 2.2 |
| First ionization energy | 1312 kJ/mol |
| Electron affinity | 72.77 kJ/mol |
| Atomic radius | 53 pm |
| Density | 0.082 g/L |
| Melting point | -259.31°C |
| Boiling point | -252.87°C |
| Specific heat | 14.3 J/(g·°C) |
Natural isotopes
- H-1: Stable (99.98%)
- H-2: Stable (0.02%)
- H-3: Radioactive (trace)
Common uses
- Ammonia Production
- Hydrogenation
Where it matters
- Energy transition (Fuel Cells)
- Hydrogen as energy carrier
- Heavy Water (D₂O) in CANDU reactors
Hazards
- Highly flammable
- Explosion risk
History
| Discovered | 1766 |
|---|---|
| Discovered by | Henry Cavendish |
| Name | Antoine Lavoisier |