Noble gases
The noble gases (helium, neon, argon, krypton, xenon, radon, oganesson) form Group 18 of the periodic table. Their full outer electron shells make them famously unreactive, which is why they are used in lighting (neon signs), as protective atmospheres (argon welding) and as low-temperature refrigerants (liquid helium).
Browse by
| No. | Symbol | Element | Atomic weight (u) | Density (g/cm³) | Melting point (K) | Boiling point (K) | Electronegativity | Discovered |
|---|---|---|---|---|---|---|---|---|
| 2 | He | Helium | 4.0026 | 0.1786 | 0.95 | 4.222 | - | 1868 |
| 10 | Ne | Neon | 20.1797 | 0.9002 | 24.56 | 27.104 | - | 1898 |
| 18 | Ar | Argon | 39.792 | 1.784 | 83.81 | 87.302 | - | 1894 |
| 36 | Kr | Krypton | 83.7982 | 3.749 | 115.78 | 119.93 | 3 | 1898 |
| 54 | Xe | Xenon | 131.294 | 5.894 | 161.4 | 165.051 | 2.6 | 1898 |
| 86 | Rn | Radon | 222 | 9.73 | 202 | 211.5 | 2.2 | 1899 |
| 118 | Og | Oganesson | 294 | 4.95 | - | 350 | - | 2002 |