1 H
Reactive nonmetal
Hydrogen
Most abundant element in the universe.
Properties of Hydrogen
- Atomic number (Z)
- 1
- Symbol
- H
- Atomic mass
- 1.008 g/mol
- Category
- Reactive nonmetal
- Group
- 1
- Period
- 1
- Electron configuration
- 1s¹
- Electronegativity (Pauling)
- 2.2
- Atomic radius
- 53 pm
- First ionization energy
- 1312 kJ/mol
- Melting point
- 13.99 K (-259.2 °C)
- Boiling point
- 20.27 K (-252.9 °C)
- Density
- 0.0000899 g/cm³
- Phase at 25 °C
- Gas
- Discovered
- Discovered in 1766