Xe Xenon

Quick answerXenon (Xe) is a noble gas with atomic number 54 and an atomic mass of 131.29 (2023), in group 18, period 5. It was discovered by William Ramsay and Morris Travers in 1898. It is used for cinema projectors and car headlights. Its electron configuration is [Kr] 4d10 5s2 5p6.

Xenon is a heavy noble gas that lights cinema projectors, car headlights, and the ion engines of deep-space probes.

Key facts

Symbol	Xe
Atomic number	54
Atomic mass	131.29 (IUPAC standard atomic weight, 2023)
Category	noble gas
Group	18
Period	5
Block	p-block
Electron configuration	[Kr] 4d10 5s2 5p6
Discovered	William Ramsay and Morris Travers, 1898
Uses	cinema projectors, car headlights, ion thrusters, medical anaesthesia, lasers

Quick quiz

Three questions from the facts on this page. No sign-up, no score is saved.

1. What is the chemical symbol of Xenon?

Ar He Ne Xe

2. What is the atomic number of Xenon?

54 56 55 53

3. Which category does Xenon belong to?

alkali metal noble gas transition metal halogen

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Keep exploring

• Periodic table — all 118 elements
• Helium (He) — another noble gas, atomic number 2
• Neon (Ne) — another noble gas, atomic number 10
• Argon (Ar) — another noble gas, atomic number 18
• Krypton (Kr) — another noble gas, atomic number 36
• Radon (Rn) — another noble gas, atomic number 86
• Oganesson (Og) — another noble gas, atomic number 118

Sources & last updated

• CIAAW — Standard Atomic Weights
• PubChem Periodic Table
• Wikipedia — Timeline of chemical element discoveries

Last updated: 2026-11-12. Figures are shown with their year; where sources disagree, the value is left out rather than estimated.