8 O 15.999

Oxygen

diatomic nonmetal

Properties

Atomic number
8
Atomic mass
15.999 u
Category
diatomic nonmetal
Group
16
Period
2
Block
p-block
State (room temp)
Gas
Outer-shell electrons
6
Electronegativity
3.44 (Pauling)
Density
-
Melting point
-218.79 °C
Boiling point
-182.96 °C

Electron configuration

1s² 2s² 2p⁴

Noble-gas shorthand: [He] 2s² 2p⁴

Electrons per shell: 2, 6, which is 6 in the outermost shell.

Related: electron configuration, the Bohr model, valence electrons.

O
Bohr model; outer-shell electrons in blue

About Oxygen

Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetal and oxidizing agent that readily forms compounds (notably oxides) with most elements. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium.

Oxygen: frequently asked questions

What is Oxygen?
Oxygen (O) is the chemical element with atomic number 8. It is a nonmetal (diatomic nonmetal).
What is the atomic number of Oxygen?
Oxygen's atomic number is 8, which means every Oxygen atom has 8 protons in its nucleus.
What is the electron configuration of Oxygen?
The electron configuration of Oxygen is 1s2 2s2 2p4 (noble-gas shorthand: [He] 2s2 2p4). Its electrons are arranged in shells of 2, 6, with 6 in the outermost shell.
Is Oxygen a metal or a nonmetal?
Oxygen is a nonmetal (diatomic nonmetal).
What group and period is Oxygen in?
Oxygen is in group 16 and period 2 of the periodic table.
Is Oxygen a solid, liquid, or gas?
At room temperature, Oxygen is a gas.

Position in the periodic table

Open the interactive periodic table →

Data compiled from Wikipedia, PubChem, and IUPAC. Source.