Argon vs Krypton
| Property | Ar Argon | Kr Krypton |
|---|---|---|
| Atomic number | 18 | 36 |
| Symbol | Ar | Kr |
| Name | Argon | Krypton |
| Category | noble-gas | noble-gas |
| Standard Atomic Weight | 39.948 u | 83.798 u |
| Period | 3 | 4 |
| Group | 18 | 18 |
| Block | p | p |
| Phase at STP | gas | gas |
| Electron configuration | [Ne]3s23p6 | [Ar]4s23d104p6 |
| Oxidation states | [0] | [0, 1, 2] |
| Electronegativity (Pauling) | N/A | 3 |
| Electron affinity | -1 eV | -1 eV |
| Density | 1.7837 kg/m³ | 3.733 kg/m³ |
| Melting point | -189.35 °C | -157.36 °C |
| Boiling point | -185.85 °C | -153.42 °C |
| Discovery year | 1894 | 1898 |