Argon |
| Symbol | Ar |
|---|---|
| Latin name | Argon |
| Atomic number | 18 |
| Period | 3 |
| Element category | Noble gases |
| Relative atomic mass | 39.948 |
| Group | VIII.A |
| 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 |