Oxygen
Reactive Nonmetal
Oxygen (O) is a chemical element with atomic number 8, classified as a reactive nonmetal. At room temperature it is a gas. It was discovered in 1774 by Joseph Priestley, Carl Wilhelm Scheele.
Properties
- Atomic number
- 8
- Atomic mass
- 15.999 u
- Category
- Reactive Nonmetal
- Group
- 16
- Period
- 2
- Block
- p-block
- Electron configuration
- [He] 2s² 2p⁴
- Phase at STP
- Gas
- Density
- 1.429 g/L
- Melting point
- 54.36 K (-218.8 °C)
- Boiling point
- 90.2 K (-182.9 °C)
- Electronegativity
- 3.44
- Atomic radius
- 48 pm
- Ionization energy
- 13.618 eV
- Discovery
- 1774 · Joseph Priestley, Carl Wilhelm Scheele
Common uses
Breathing, combustion, steel production, water
Did you know?
Essential for most life forms and the most abundant element in Earth's crust.