| Argon ✕ | |
|---|---|
| Symbol | Ar |
| Atomic number | 18 |
| Chemical property | Noble gas |
| Origin o the name | the Greek argos, 'idle' |
| Group | 18 |
| Period | 3 |
| Atomic weight (u) | 39.948 |
| Atomic weight uncertainty (u) | 0.001 |
| Density (g/cm³) | 0.001784 |
| Melting point (K) | 83.8 |
| Boiling point (K) | 87.3 |
| Heat capacity (J/(g·K)) | 0.52 |
| Abundance in earth's crust (mg/kg) | 3.5 |