1 H 1.008

Hydrogen

Reactive Nonmetal

Hydrogen (H) is a chemical element with atomic number 1, classified as a reactive nonmetal. At room temperature it is a gas. It was discovered in 1766 by Henry Cavendish.

Properties

Atomic number
1
Atomic mass
1.008 u
Category
Reactive Nonmetal
Group
1
Period
1
Block
s-block
Electron configuration
1s¹
Phase at STP
Gas
Density
0.08988 g/L
Melting point
13.99 K (-259.2 °C)
Boiling point
20.27 K (-252.9 °C)
Electronegativity
2.2
Atomic radius
53 pm
Ionization energy
13.598 eV
Discovery
1766 · Henry Cavendish

Common uses

Fuel cells, rocket fuel, ammonia production

Did you know?

The most abundant element in the universe, making up about 75% of all matter.