Oxygen vs Calcium
| Property | O Oxygen | Ca Calcium |
|---|---|---|
| Atomic number | 8 | 20 |
| Symbol | O | Ca |
| Name | Oxygen | Calcium |
| Category | nonmetal | alkaline-earth-metal |
| Standard Atomic Weight | 15.9994 u | 40.078 u |
| Period | 2 | 4 |
| Group | 16 | 2 |
| Block | p | s |
| Phase at STP | gas | solid |
| Electron configuration | [He]2s22p4 | [Ar]4s2 |
| Oxidation states | [-2, -1, 0, 1, 2] | [1, 2] |
| Electronegativity (Pauling) | 3.44 | 1 |
| Electron affinity | 1.4611 eV | 0.0245 eV |
| Density | 1.429 kg/m³ | 1540 kg/m³ |
| Melting point | -218.79 °C | 841.85 °C |
| Boiling point | -182.95 °C | 1483.85 °C |
| Discovery year | 1771 | 1808 |