argon

Symbol: Ar
Atomic number: 18
Atomic weight: 39.948
Group: 18
Group name: Noble gas
Period: 3
Block: p
CAS ID: 7440-37-1
Shell structure: 2.8.8
Electron configuration: [Ne].3s2.3p6
State: |standardstate|
Melting point: 83.8 [or -189.3 °C (-308.7 °F)]
Boiling point: 87.3 [or -185.8 °C (-302.4 °F)]
Ionization energy/kJ per mol: 1520.6
Common oxidation states: 0
Pauling electronegativity: no data