Argon

Symbol | Ar
Latin name | Argon
Atomic number | 18
Period | 3
Element category | Noble gases
Relative atomic mass | 39.948
Group | VIII.A
Oxidation numbers |
Electron configuration | 1s2 2s2 2p6 3s2 3p6
Density [g/cm3] | 0.0017838
State | Gas
Melting point [°C] | -189.4
Boiling point [°C] | -185.87
Critical point [°C] | -86.28
Critical pressure [MPa] | 4.988
Atomic radius [pm] | 71
Covalent radius [pm] | 97
Thermal conductivity [W m-1K-1] | 0.0177
Heat capacity [J K-1g-1] | 0.52
Discovery | 1894
1.st ionization energy [eV] | 15.7596
2.nd ionization energy [eV] | 27.629
3.rd ionization energy [eV] | 40.74
Stable isotopes | 3
Unstable isotopes | 5