Oxygen (O)
Oxygen (O, element 8) is a nonmetal in group 16, period 2. Atomic mass 15.999, electron configuration [He] 2s² 2p⁴, uses and facts.
About Oxygen
Oxygen is a nonmetal with the symbol O and atomic number 8. It is a gas at room temperature, and it sits in group 16, period 2 of the periodic table. Oxygen was discovered in 1774 by Joseph Priestley.
Oxygen key facts
- Atomic number: 8
- Symbol: O
- Atomic mass: 15.999 u
- Category: nonmetal
- Group: 16
- Period: 2
- State at room temperature: gas
- Electron configuration: [He] 2s² 2p⁴
- Electronegativity (Pauling): 3.44
- Melting point: 54.36 K (-218.79 °C)
- Boiling point: 90.2 K (-182.95 °C)
- Density: 0.001429 g/cm³
- Common oxidation states: −2, −1, 0, +1, +2
Electron configuration
The electron configuration of oxygen is [He] 2s² 2p⁴. The part in brackets is the noble gas core; the rest shows how the outer electrons fill their subshells. Oxygen has 6 valence electrons.
Uses of oxygen
- Breathing
- Steel making
- Water treatment
Did you know?
Liquid oxygen is pale blue and strongly magnetic.
Other elements in group 16 and neighbours
Frequently asked questions
What is the atomic number of oxygen?
The atomic number of oxygen is 8, which means every oxygen atom has 8 protons.
What is the electron configuration of oxygen?
The electron configuration of oxygen is [He] 2s² 2p⁴.
What group and period is oxygen in?
Oxygen is a nonmetal in group 16, period 2.
What state is oxygen at room temperature?
Oxygen is a gas at room temperature.
What is oxygen used for?
Oxygen is used for breathing, steel making, water treatment.