Argon

Atomic number

18

Atomic mass (u)

39.9

Category

Noble gas

Standard state

Gas

Melting point

-189.35 °C (83.8 K)

Boiling point

-185.85 °C (87.3 K)

Density (g/cm³)

0.0017837

Electronegativity (Pauling)

Not reported in this source

Electron configuration

[Ne]3s2 3p6

Oxidation states

0

Atomic radius (pm)

188

First ionization energy (eV)

15.760

Discovery & recognition

Discovery year / period (PubChem)

1894

Discovery credited to (RSC)

Lord Rayleigh and Sir William Ramsay

Date or period recorded by RSC

1894

Discovery place

Not supplied in the structured record; see the RSC history source.

An ancient date does not identify a first human discovery. Different references may date observation, isolation and formal recognition differently.

Natural occurrence & production

The creation of an element’s nuclei and its concentration into terrestrial deposits are different processes. The occurrence note below concerns its presence or production on Earth; it is not a complete account of nucleosynthesis.

“Argon makes up 0.94% of the Earth’s atmosphere and is the third most abundant atmospheric gas.”

Royal Society of Chemistry · occurrence excerpt ↗

Continue the research

Reference values are not product specifications. Blank values have not been estimated. For superheavy elements, some properties and family assignments are theoretical or incompletely measured.