Helium vs Yttrium
| Property | He Helium | Y Yttrium |
|---|---|---|
| Atomic number | 2 | 39 |
| Symbol | He | Y |
| Name | Helium | Yttrium |
| Category | noble-gas | transition-metal |
| Standard Atomic Weight | 4.002602 u | 88.90584 u |
| Period | 1 | 5 |
| Group | 18 | 3 |
| Block | s | s |
| Phase at STP | gas | solid |
| Electron configuration | 1s2 | [Kr]5s24d1 |
| Oxidation states | [0] | [0, 1, 2, 3] |
| Electronegativity (Pauling) | N/A | 1.22 |
| Electron affinity | -0.5 eV | 0.307 eV |
| Density | 0.1785 kg/m³ | 4470 kg/m³ |
| Melting point | -272.2 °C | 1521.85 °C |
| Boiling point | -268.93 °C | 3344.85 °C |
| Discovery year | 1868 | 1794 |