Symbol
Ar
Atomic Number
18
Atomic Mass
39.948
Protons
18
Neutrons
22
Electrons
18
Type
Noble Gas
Isotopes
Argon-36, Argon-38, Argon-40
Discovery Year
1894
Discovered By
Lord Rayleigh, William Ramsay
Group
18
Period
3
Boiling Point
-303°F
Melting Point
-308°F
Electron Configuration
[Ne] 3s² 3p⁶
Density (g/cm³)
0.001784
Crystal Structure
Face-centered cubic
Magnetism
Diamagnetic
Abundance in Earth's Crust
0.00015%
Phase at Room Temperature
Gas