Ar
Argon Symbol (Ar)
Argon is element 18 of the periodic table. Copy its symbol Ar and see its atomic weight, electron configuration and common compounds.
What does Ar mean?
Ar is the chemical symbol for argon, element number 18 in the periodic table. Argon is a noble gas in group 18, period 3. It is the third most abundant gas in air (about 0.93%), used as a shielding gas in welding.
Codes and properties
| Chemical symbol | Ar |
|---|---|
| Atomic number (Z) | 18 |
| Standard atomic weight | 39.948 |
| Group / period | 18 / 3 |
| Element category | noble gas |
| Electron configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ |
How to type Ar
- Plain text: type
Ar— element symbols are ordinary Latin letters, with the first letter capitalised and the second lowercase. - Subscripts in formulas: use Unicode subscript digits (₀₁₂₃₄₅₆₇₈₉) for formulas such as H₂O — copy them from the chemistry keyboard.
- LaTeX: write
\mathrm{Ar}in math mode, or use the mhchem package:\ce{Ar}. - HTML:
Ar; for subscripts use<sub>, e.g.H<sub>2</sub>O.
Frequently asked questions
What is the chemical symbol for argon?
The chemical symbol for argon is Ar.
What is the atomic number of argon?
Argon has atomic number 18, meaning each atom has 18 protons.
What is the electron configuration of argon?
The ground-state electron configuration of argon is 1s² 2s² 2p⁶ 3s² 3p⁶.