054Noble gas · Group 18 · Period 5
Xenon
Xenon (Xe) is element 54, a noble gas in the p-block — group 18, period 5. It is a gas at room temperature with 5 electron shells (2, 8, 18, 18, 8) and an atomic mass of 131.2936 u.
- Atomic mass
- 131.3 u
- Phase · STP
- gas
- Melting
- 161 K · -112 °C
- Boiling
- 165 K · -108 °C
- Electronegativity
- 2.6
- Density
- 5.894 g/cm³
Photograph — Jurii, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons, source: https://images-of-elements.com/xenon.php
Emission spectrum
The visible light Xenon emits when energised — its unique spectral fingerprint.
Identity
- Atomic number
- 54
- Standard atomic weight
- 131.3 u
- Category
- Noble gas
- Group
- 18 · Noble gases
- Period
- 5
- Block
- p-block
- Oxidation states
- 0
Physical properties
- Melting point
- 161 K · -112 °C
- Boiling point
- 165 K · -108 °C
- Density
- 5.894 g/cm³
- Molar heat capacity
- —
- Atomic radius
- 216 pm
- Electron affinity
- -77 kJ/mol
Atomic structure
54protons
77neutrons
54electrons
8valence e⁻
- Noble-gas notation
- [Kr] 4d10 5s2 5p6
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6
- Electrons per shell
- 2, 8, 18, 18, 8
Periodic trends
Where Xenon ranks across all 118 elements.
Ionization energies
Energy to remove each successive electron (kJ/mol).
1.2k1
2.0k2
3.1k3
Successive ionization energies (kJ/mol, log scale).
Discovery
- Discovered
- 1898
- Discovered by
- William Ramsay
- Named by
- —
- Appearance
- colorless gas, exhibiting a blue glow when placed in a high voltage electric field