Argon (Ar)
Argon
Argon (Ar) is a noble gas in period 3, group 18. Its relative atomic mass is 39.948 and the molar mass of the atom is 39.948 g/mol.
Atomic number 18
Atomic mass 39.948
Molar mass 39.948 g/mol
Category Noble gas Gas
Properties of argon
| Atomic number | 18 |
|---|---|
| Symbol | Ar |
| Latin name | Argon |
| Relative atomic mass | 39.948 |
| Molar mass | 39.948 g/mol |
| Group, period, block | 18, 3, p |
| Category | Noble gas |
| State at 20 °C | Gas |
| Electron configuration | [Ne] 3s² 3p⁶ |
| Atomic radius | 71 pm |
Electron configuration of argon
Electrons per shell
K2L8M8
Full notation
1s² 2s² 2p⁶ 3s² 3p⁶
Noble-gas notation
18 protons · 18 electrons[Ne] 3s² 3p⁶
Formula and compounds of argon
Simple substanceArargonMolar mass of Ar: 39.948 g/mol
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Frequently asked questions
The relative atomic mass of argon is 39.948, so the molar mass of the atom is 39.948 g/mol.
Full: 1s² 2s² 2p⁶ 3s² 3p⁶. Noble-gas notation: [Ne] 3s² 3p⁶.