Element 54 · Noble gas
Xenon (Xe) — Element 54
Greek xenos — stranger
Xenon (Xe) is a noble gas in Period 5, Group 18 of the periodic table with atomic number 54, standard atomic weight 131.29 u, and ground-state electron configuration [Kr] 4d¹⁰ 5s² 5p⁶. At standard temperature and pressure it is classified as a gas with 0 valence electrons and common oxidation states 0.
Lighting, anesthesia, ion thrusters
What are the atomic properties and physical constants of Xenon?
Reference constants compiled from IUPAC standard atomic weights, the NIST Atomic Spectra Database, and the CRC Handbook.
- Atomic number (Z)
- 54
- Standard atomic mass
- 131.29 u
- Chemical family
- Noble gas
- Ground-state configuration
- [Kr] 4d¹⁰ 5s² 5p⁶
- Electrons per shell
- 2, 8, 18, 18, 8
- Valence electrons
- 0
- Common ion charges / oxidation states
- 0
- Phase at STP
- Gas
- Pauling electronegativity
- 2.60 Pauling
- First ionization energy
- 1,170 kJ/mol
- Atomic radius
- 108 pm
- Melting point
- -112 °C
- Boiling point
- -108 °C
- Discovery year
- 1898
- Table coordinate
- Period 5, Group 18
- Radioactivity
- Has stable isotope(s)
How are electrons arranged across Xenon’s shells?
A neutral Xenon atom contains 54 electrons distributed across 5 occupied principal energy shells ([Kr] 4d¹⁰ 5s² 5p⁶). The table below compares Xenon’s shell occupancy against each shell’s theoretical 2n² capacity.
| Principal Shell (n) | Spectroscopic Letter | Electrons in Xe | Max Shell Capacity (2n²) |
|---|---|---|---|
| n = 1 | K | 2 e⁻ | 2 e⁻ |
| n = 2 | L | 8 e⁻ | 8 e⁻ |
| n = 3 | M | 18 e⁻ | 18 e⁻ |
| n = 4 | N | 18 e⁻ | 32 e⁻ |
| n = 5 | O | 8 e⁻ | 50 e⁻ |
Frequently Asked Questions about Xenon (Xe)
What is the atomic mass and atomic number of Xenon (Xe)?
Xenon (Xe) has atomic number Z = 54 (54 protons in its nucleus) and an IUPAC standard atomic weight of 131.29 u. It sits in Period 5, Group 18 and is classified as a noble gas.
What is the ground-state electron configuration of Xenon?
The neutral ground-state electron configuration of Xenon (Z = 54) is [Kr] 4d¹⁰ 5s² 5p⁶. Across its 5 occupied principal shells (n = 1 to n = 5), the electrons per shell are 2, 8, 18, 18, 8, with 0 valence electrons participating in bonding.
What are the common ion charges and electronegativity of Xenon?
Xenon commonly forms 0 oxidation states or ion charges in compounds. Its Pauling electronegativity is 2.60 and its first ionization energy is 1,170 kJ/mol.
When was Xenon discovered and what is it used for?
Xenon was discovered in 1898 (Greek xenos — stranger). Lighting, anesthesia, ion thrusters
How does Xenon compare to neighboring elements?
Other noble gas elements: