Argon vs Radium
| Property | Ar Argon | Ra Radium |
|---|---|---|
| Atomic number | 18 | 88 |
| Symbol | Ar | Ra |
| Name | Argon | Radium |
| Category | noble-gas | alkaline-earth-metal |
| Standard Atomic Weight | 39.948 u | 226 u |
| Period | 3 | 7 |
| Group | 18 | 2 |
| Block | p | s |
| Phase at STP | gas | solid |
| Electron configuration | [Ne]3s23p6 | [Rn]7s2 |
| Oxidation states | [0] | [2] |
| Electronegativity (Pauling) | N/A | 0.9 |
| Electron affinity | -1 eV | 0.096 eV |
| Density | 1.7837 kg/m³ | 5000 kg/m³ |
| Melting point | -189.35 °C | 699.85 °C |
| Boiling point | -185.85 °C | 1139.85 °C |
| Discovery year | 1894 | 1898 |