Helium vs Phosphorus
| Property | He Helium | P Phosphorus |
|---|---|---|
| Atomic number | 2 | 15 |
| Symbol | He | P |
| Name | Helium | Phosphorus |
| Category | noble-gas | nonmetal |
| Standard Atomic Weight | 4.002602 u | 30.973762 u |
| Period | 1 | 3 |
| Group | 18 | 15 |
| Block | s | p |
| Phase at STP | gas | solid |
| Electron configuration | 1s2 | [Ne]3s23p3 |
| Oxidation states | [0] | [-3, -2, -1, 0, 1, 2, 3, 4, 5] |
| Electronegativity (Pauling) | N/A | 2.19 |
| Electron affinity | -0.5 eV | 0.7466 eV |
| Density | 0.1785 kg/m³ | 1820 kg/m³ |
| Melting point | -272.2 °C | 44.15 °C |
| Boiling point | -268.93 °C | 280.5 °C |
| Discovery year | 1868 | 1669 |