Noble gases7 elements · group 18
The noble gases make up group 18: helium, neon, argon, krypton, xenon, radon and oganesson. Their outer electron shells are full, so they are very stable and rarely react — for a long time they were called the inert gases. They are colourless, odourless and exist as single atoms. They glow brightly in electric discharges and are used in lighting, welding and cryogenics.
# Properties of noble gases
- Full outer electron shell
- Very unreactive (xenon and krypton can form a few compounds)
- Monatomic, colourless and odourless gases
- Highest ionization energy in each period
- Used in signs, lasers, welding and balloons
# List of noble gases
| # | Symbol | Element | Atomic mass | Electron configuration | State at 25 °C | Melting point |
|---|---|---|---|---|---|---|
| 2 | He | Helium | 4.003 | 1s² | gas | 0.95 K |
| 10 | Ne | Neon | 20.18 | [He] 2s² 2p⁶ | gas | 24.56 K |
| 18 | Ar | Argon | 39.948 | [Ne] 3s² 3p⁶ | gas | 83.8 K |
| 36 | Kr | Krypton | 83.798 | [Ar] 3d¹⁰ 4s² 4p⁶ | gas | 115.79 K |
| 54 | Xe | Xenon | 131.29 | [Kr] 4d¹⁰ 5s² 5p⁶ | gas | 161.4 K |
| 86 | Rn | Radon | 222 | [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶ | gas | 202 K |
| 118 | Og | Oganesson | [294] | [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁶ | predicted solid | 325 K |
# Noble gases FAQ
Which elements are noble gases?
There are 7 noble gases in this table: Helium, Neon, Argon, Krypton, Xenon, Radon, Oganesson.
Where are the noble gases on the periodic table?
The noble gases are found in group 18, the far-right column.
What are the properties of noble gases?
Full outer electron shell; Very unreactive (xenon and krypton can form a few compounds); Monatomic, colourless and odourless gases; Highest ionization energy in each period; Used in signs, lasers, welding and balloons.