| Atomic number | : | 18 |
| Atomic mass | : | 39.948 g.mol-1 |
| Electronegativity according to Pauling | : | unknown |
| Density | : | 1.78*10-3 g.cm-3 at 20 °C |
| Melting point | : | - 189 °C |
| Boiling point | : | - 185.7 °C |
| Vanderwaals radius | : | 0.192 nm |
| Ionic radius | : | unknown |
| Isotopes | : | 6 |
| Electronic shell | : | [Ne]3s23p6 |
| Energy of first ionisation | : | 1520 kJ.mol-1 |
| Energy of second ionisation | : | 2665.8 kJ.mol-1 |
| Energy of third ionisation | : | 3931 kJ.mol-1 |
| Discovered by | : | Sir Ramsay in 1894 |
Periodic Table of Elements
