Oxygen (O) — Element 8: Properties & Data
Oxygen (O) is a nonmetal with atomic number 8 and atomic mass 15.999. It has melting point 54.36 K (-219 °C), boiling point 90.2 K (-183 °C), density 0.001429 g/cm³. It sits in group 16 and period 2 of the periodic table and was discovered in 1774.
For research use only. Not for human or veterinary diagnostic or therapeutic use.
Key facts
| Atomic mass | 15.999 u |
|---|---|
| Electron configuration | [He]2s2 2p4 |
| Oxidation states | -2 |
| Electronegativity (Pauling) | 3.44 |
| Atomic radius (van der Waals) | 152 pm |
| Ionization energy | 13.618 eV |
| Electron affinity | 1.461 eV |
| Melting point | 54.36 K |
| Boiling point | 90.2 K |
| Density | 0.001429 g/cm³ |
| Standard state | Gas |
| Discovered | 1774 |
Domande frequenti
What is the electron configuration of oxygen?
The ground-state electron configuration of oxygen is [He]2s2 2p4.
What group and period is oxygen in?
Oxygen (O) is in group 16 and period 2 of the periodic table, classified as a nonmetal.
What is the melting point of oxygen?
Oxygen melts at 54.36 K (-219 °C).
What is the standard state of oxygen?
Oxygen is a gas at standard temperature and pressure.
Related elements
Informazioni su questi dati: property values compiled from IUPAC Standard Atomic Weights (2021), the NIST Atomic Spectra Database, and PubChem. Curated by the Aladdin Scientific technical team. Last reviewed: .