ElementsWhat is xenon?
Xenon is a heavy, rare gas found in tiny amounts in air. It was the first noble gas shown to form compounds.
What is xenon used for?
Bright car headlamps and camera flashes, cinema projector lamps, and engines that move satellites in space.
Where the name comes from
From the Greek word xenos, stranger.
Key facts
- Symbol
- Xe
- Atomic number
- 54
- Atomic mass
- 131.29 u
- Family
- Noble gas
- Period
- 5
- Group
- 18
- Block
- p
- State at room temperature
- Gas
- Melting point
- -111.8 °C (161.36 K, -169 °F)
- Boiling point
- -108.1 °C (165.03 K, -163 °F)
- Density
- 0.005887 g/cm³ (as a gas at 0 °C)
- Electrons per shell
- 2, 8, 18, 18, 8
- Electron configuration
- [Kr]5s2 4d10 5p6
- Common oxidation states
- 0
- Electronegativity (Pauling)
- 2.6
- First ionisation energy
- 12.13 eV
- Electron affinity
- no value
- Atomic radius (van der Waals)
- 216 pm
- Discovered
- 1898
Place in the periodic table
Xenon is element number 54. It sits in period 5 (row 5) of the periodic table, in group 18 (column 18), and belongs to the p-block. Just before it comes iodine (53), and just after it comes caesium (55). In the same column, krypton is above it and radon is below it. Elements in one column tend to behave alike.
Family: Noble gases.
Physical properties
At room temperature xenon is a gas. It melts at -111.8 °C and boils at -108.1 °C, so it stays liquid over a range of 4 degrees. One litre of the gas weighs about 5.887 grams at 0 °C and normal pressure. That is heavier than air, which weighs about 1.29 grams a litre. It has the 9th lowest melting point of all elements.
Inside the atom
An atom of xenon has 54 protons in its nucleus and, when neutral, 54 electrons around it. The electrons are arranged in 5 shells: 2, 8, 18, 18, 8. The outermost shell holds 8 electrons. Written in full, the electron configuration is [Kr]5s2 4d10 5p6.
Its electronegativity on the Pauling scale is 2.6. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 12.13 electronvolts (about 1,170 kilojoules per mole). One mole of xenon weighs 131.29 grams, so a single gram contains about 4.59 × 1021 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains xenon with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.