54131.29XeXenon
Xenon (Xe) — element 54noble gas · group 18, period 5
Xenon is a chemical element with the symbol Xe and atomic number 54. It is a noble gas in group 18, period 5 of the periodic table (the p-block), with a standard atomic mass of 131.29 u. At room temperature (25 °C) xenon is a gas.
💡 Known for: Used in bright car headlights, in ion thrusters for spacecraft and as a general anaesthetic.
# Xenon properties
| Symbol | Xe |
|---|---|
| Atomic number | 54 |
| Atomic mass | 131.29 u |
| Category | noble gas |
| Group | 18 |
| Period | 5 |
| Block | p-block |
| Electron configuration | [Kr] 4d¹⁰ 5s² 5p⁶ |
| Full configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ |
| Electrons per shell | 2, 8, 18, 18, 8 |
| Protons / electrons | 54 / 54 |
| State at 25 °C | gas |
| Melting point | 161.4 K (-111.7 °C, -169.1 °F) |
| Boiling point | 165.03 K (-108.1 °C, -162.6 °F) |
| Density | 5.887 g/L |
| Electronegativity (Pauling) | 2.6 |
| First ionization energy | 12.13 eV |
| Atomic radius | 108 pm |
| Discovered | 1898 |
# Electron configuration of xenon
The electron configuration of xenon is [Kr] 4d¹⁰ 5s² 5p⁶, written out in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶. Its 54 electrons fill 5 shells as 2, 8, 18, 18, 8, so the outermost shell holds 8 electrons. As a group 18 element, xenon has 8 valence electrons.
# Related elements
IIodineprevious elementCsCaesiumnext elementHeHeliumgroup 18NeNeongroup 18ArArgongroup 18KrKryptongroup 18RnRadongroup 18OgOganessongroup 18
# Xenon FAQ
What is the atomic number of xenon?
The atomic number of xenon is 54: every xenon atom has 54 protons in its nucleus. Its symbol is Xe.
What is the atomic mass of xenon?
The standard atomic mass of xenon is 131.29 u.
What is the electron configuration of xenon?
Xenon's electron configuration is [Kr] 4d¹⁰ 5s² 5p⁶ (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶), with 2, 8, 18, 18, 8 electrons per shell.
Is xenon a metal?
No. Xenon is a noble gas, a nonmetal.
What is the melting point of xenon?
Xenon melts at 161.4 K (-111.7 °C, -169.1 °F) and boils at 165.03 K (-108.1 °C, -162.6 °F).
What is xenon used for / known for?
Used in bright car headlights, in ion thrusters for spacecraft and as a general anaesthetic.