Helium vs Zirconium
| Property | He Helium | Zr Zirconium |
|---|---|---|
| Atomic number | 2 | 40 |
| Symbol | He | Zr |
| Name | Helium | Zirconium |
| Category | noble-gas | transition-metal |
| Standard Atomic Weight | 4.002602 u | 91.224 u |
| Period | 1 | 5 |
| Group | 18 | 4 |
| Block | s | s |
| Phase at STP | gas | solid |
| Electron configuration | 1s2 | [Kr]5s24d2 |
| Oxidation states | [0] | [1, 2, 3, 4] |
| Electronegativity (Pauling) | N/A | 1.33 |
| Electron affinity | -0.5 eV | 0.426 eV |
| Density | 0.1785 kg/m³ | 6520 kg/m³ |
| Melting point | -272.2 °C | 1854.85 °C |
| Boiling point | -268.93 °C | 4408.85 °C |
| Discovery year | 1868 | 1789 |