Quick answerArgon (Ar) is a noble gas with atomic number 18 and an atomic mass of 39.948 (2023), in group 18, period 3. It was discovered by Lord Rayleigh and William Ramsay in 1894. It is used for welding shielding gas and light bulb filling. Its electron configuration is [Ne] 3s2 3p6.
Argon is the lazy gas that fills light bulbs and welders' shields, protecting hot metal from the air without reacting at all.
Key facts
| Symbol | Ar |
|---|---|
| Atomic number | 18 |
| Atomic mass | 39.948 (IUPAC standard atomic weight, 2023) |
| Category | noble gas |
| Group | 18 |
| Period | 3 |
| Block | p-block |
| Electron configuration | [Ne] 3s2 3p6 |
| Discovered | Lord Rayleigh and William Ramsay, 1894 |
| Uses | welding shielding gas, light bulb filling, preserving documents and wine, double-glazed windows, plasma cutting |
Quick quiz
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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
- Krypton (Kr) — another noble gas, atomic number 36
- Xenon (Xe) — another noble gas, atomic number 54
- 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: . Figures are shown with their year; where sources disagree, the value is left out rather than estimated.