Element 8
Oxygen
Nonmetals
Oxygen (O) is in the p-block of the periodic table — group 16, period 2.
Oxygen is a chemical element with symbol O and atomic number 8.
Key data
- Atomic number
- 8
- Atomic mass
- 15.999 u
- Group / Period
- 16 / 2
- Block
- p-block
- Phase at STP
- Gas
- Density
- 1.429 g/cm³
- Melting point
- -218.8 °C
- Boiling point
- -183.0 °C
- Electron configuration
- [He] 2s2 2p4
Periodic table block
Oxygen is in the p-block (group 16, period 2). Elements land in the p-block when their highest-energy electrons fill a p subshell — this region holds most nonmetals, the metalloids, and the metals on the right of the table.
New to this? Periodic table blocks explained: s, p, d, and f
Common uses
- •Steelmaking
- •Medical respiration
- •Half of Earth's crust
Discovery
Year: 1774
Discovered by: Carl Wilhelm Scheele
Named by: Antoine Lavoisier
Frequently asked questions
What is the atomic number of Oxygen?
Oxygen has atomic number 8. Its symbol is O and its atomic mass is 15.999 u.
What category of element is Oxygen?
Oxygen is classified as nonmetals. It sits in group 16, period 2 of the periodic table.
What block of the periodic table is Oxygen in?
Oxygen is in the p-block (group 16, period 2). Its highest-energy electrons occupy the p subshell — you can see this in its electron configuration, [He] 2s2 2p4.
What is Oxygen used for?
Common uses of Oxygen include: Steelmaking, Medical respiration, Half of Earth's crust.
When was Oxygen discovered?
Oxygen was discovered in 1774 by Carl Wilhelm Scheele.
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