Oxygen (O): Electron Configuration, Properties and Uses
Oxygen (O): Electron Configuration, Properties and Uses
Electron configuration [He] 2s2 2p4 · group 16 · period 2 · Ar 15.999
Oxygen data
- Atomic number
- 8
- Relative atomic mass
- 15.999
- Group
- 16
- Period
- 2
- Block
- p
- Category
- Nonmetal
- Electron configuration
- [He] 2s2 2p4
- Full configuration
- 1s2 2s2 2p4
- Electrons per shell
- 2, 6 (K L)
- Valence electrons
- 6
- Electronegativity (Pauling)
- 3.44
- First ionisation energy
- 13.618 eV
- Atomic radius (van der Waals)
- 152 pm
- State at room temperature
- Gas
- Melting point
- −219 °C
- Boiling point
- −183 °C
- Density
- 1.429 g/L (0 °C, 1 atm)
- Common oxidation states
- −2
- Discovered
- 1774
Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.
Electron shell diagram
K 2 · L 6
Orbital diagram (outer electrons)
About oxygen
Oxygen, symbol O, is element number 8 in the periodic table. It is a nonmetal in group 16, period 2, p-block. Oxygen was first discovered in 1774. At room temperature oxygen is a gas that is heavier than air (1.429 g/L) and liquefies at −183 °C.
Oxygen electron configuration
The electron configuration of oxygen is 1s2 2s2 2p4, or in short [He] 2s2 2p4. Its electrons occupy 2 shells: K = 2, L = 6. Oxygen has 6 valence electrons in the L shell (2s2 2p4), which is why it sits in group 16. In ionic compounds oxygen gains electrons to fill its outer shell: O2− = [Ne] (like neon).
Filling order: 1s2(2) → 2s2(4) → 2p4(8)
Uses of oxygen
Well-known applications of oxygen include respiration and medical oxygen, steelmaking, welding and metal cutting, and wastewater treatment. For research and analysis you can browse oxide compounds in the AMI Scientific catalogue.
Safety
Pure oxygen accelerates burning. Keep oxygen cylinders and regulators free of oil and grease. Always read the safety data sheet (SDS) before working with a chemical.
Other elements in group 16
Frequently asked questions
What is the electron configuration of oxygen?
The electron configuration of oxygen (O, atomic number 8) is 1s2 2s2 2p4, or [He] 2s2 2p4 in short. By shell: 2, 6.
How many valence electrons does oxygen have?
Oxygen has 6 valence electrons.
Which group and period is oxygen in?
Oxygen is in group 16, period 2, p-block.
What is the atomic mass of oxygen?
The relative atomic mass of oxygen is 15.999. Use it to calculate molar mass with the molar mass calculator.
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