Atomic number 18
Argon
Noble gas
Quick facts
- Atomic mass
- 39.950
- Group
- 18
- Period
- 3
- State (STP)
- gas
- Electronegativity
- —
- Common ox. states
- 0
Properties
Electron configuration
[Ne] 3s² 3p⁶
- Ionization energy
- 1520.6 kJ/mol
- Electron affinity
- -96.0 kJ/mol
- Melting point
- 83.81 K (-189.3 °C)
- Boiling point
- 87.30 K (-185.8 °C)
How it bonds
Argon has a full 3s² 3p⁶ shell and forms no stable compounds at normal conditions — about 1% of the atmosphere, but unreactive. The "noble" part of "noble gas" was named for this aloofness.
Where you meet it
- Periodic Quest challengeunlock card