54XeXenon131.293 u
Xenon (Xe)
Xenon is a noble gas with atomic number 54, in period 5 and group 18 of the periodic table. Its atomic mass is 131.293 u and its electron configuration is [Kr] 4d¹⁰ 5s² 5p⁶. Gas at 25 °C.
Key facts
| Atomic number | 54 |
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| Atomic mass | 131.293 u |
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| Category | Noble Gas |
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| Period | 5 |
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| Group | 18 |
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| Block | p |
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| Electron configuration | [Kr] 4d¹⁰ 5s² 5p⁶ |
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| Electrons per shell | 2, 8, 18, 18, 8 |
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| Electronegativity (Pauling) | 2.6 |
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| Oxidation states | +2, +4, +6, +8common in bold |
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| State at 25 °C | Gas |
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| Melting point | 161.3 K−111.85 °C |
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| Boiling point | 165.1 K−108.05 °C |
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| Density | 5.9 g/L |
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Atomic properties
| First ionization energy | 12.13 eV |
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| Electron affinity | 0 kJ/mol |
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| Atomic radius | 108 pm |
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| Covalent radius | 140 pm |
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| Van der Waals radius | 216 pm |
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| Common ions | --- |
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| Protons, neutrons, electrons | 54, 77, 54 |
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Physical and thermal properties
| Molar volume | 35.92 cm³/mol |
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| Heat of fusion | 2.3 kJ/mol |
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| Heat of vaporization | 12.64 kJ/mol |
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| Specific heat | 158.32 J/(kg·K) |
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| Thermal conductivity | 0.00565 W/(m·K) |
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| Thermal expansion | --- |
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| Mohs hardness | --- |
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| Young’s modulus | --- |
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| Crystal structure | Face-centered cubic |
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| Magnetic type | Diamagnetic |
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Identification and history
| CAS number | 7440-63-3 |
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| Latin name | Xenon |
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| Discovered by | W. Ramsay, M. Travers · 1898 |
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| Named by | --- |
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Natural isotopes
| Isotope | Mass (u) | Abundance |
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| 124Xe | 123.905885 | 0.095 % |
| 126Xe | 125.904297 | 0.089 % |
| 128Xe | 127.903531 | 1.91 % |
| 129Xe | 128.904781 | 26.401 % |
| 130Xe | 129.903509 | 4.071 % |
| 131Xe | 130.905084 | 21.232 % |
| 132Xe | 131.904155 | 26.909 % |
| 134Xe | 133.905393 | 10.436 % |
| 136Xe | 135.907214 | 8.857 % |
Data checked against PubChem (NIH), IUPAC, the NIST Atomic Spectra Database and the IAEA (NUBASE and AME), the same data you see in the app.
A dash (---) means there is no reliable published measurement. The app never makes one up.
See Xenon in the app
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Periodic Table