Atomic number 18
Argon
Noble gas
In the real world
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 dangerous is it?
1/5 · Low risk
An inert gas used to shield welds and fill light bulbs. Breathing it briefly is harmless, but it sinks and can pool in low, enclosed spaces.
- Asphyxiant
Being heavier than air, it can collect in pits and push out the oxygen there. (the danger is the room, not the gas)
Used with ventilation and oxygen monitors; low confined spaces are tested first.
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
