8
O
15.999
Oxygen (O)
Element 8 · Period 2 · Group 16
nonmetal
gas at room temp
p-block
About Oxygen
21% of Earth's atmosphere. Essential for cellular respiration and combustion.
Physical Properties
Atomic Mass
15.999 u
State at 25°C
Gas
Melting Point
-218.79 °C
Boiling Point
-182.96 °C
Density
0.001429 g/cm³
Magnetism
Paramagnetic
Atomic Properties
Electron Configuration
[He] 2s² 2p⁴
Electron Shells
2, 6
Electronegativity
3.44
Atomic Radius
48 pm
Ionization Energy
1314 kJ/mol
Oxidation States
-2, -1, +1, +2
Discovery & History
Discovered By
Carl Wilhelm Scheele
Discovery Year
1774
Named By
Antoine Lavoisier
Name origin: Greek: oxys + genes (acid-forming)
Frequently Asked Questions
- Is Oxygen a metal, nonmetal, or metalloid?
- Oxygen is classified as a nonmetal.
- What state is Oxygen in at room temperature?
- Oxygen is a gas at standard room temperature (25°C).
- What is the atomic mass of Oxygen?
- Oxygen has an atomic mass of 15.999 atomic mass units (u).
- Who discovered Oxygen?
- Oxygen was discovered by Carl Wilhelm Scheele in 1774.
- Where is Oxygen on the periodic table?
- Oxygen is element number 8, located in period 2 and group 16.