Compare Hydrogen vs Oxygen
Comparing Hydrogen (H) and Oxygen (O). Atomic numbers 1 and 8 with atomic masses 1.008 u and 15.999 u, classified as nonmetal and nonmetal. Below: a side-by-side comparison of their physical, atomic, electron-configuration and historical properties, including density, melting and boiling points, ionization energies, oxidation states and discovery history.
Periodic properties of the elements
| Hydrogen | Oxygen | |
|---|---|---|
| Symbol | H | O |
| Atomic number | 1 | 8 |
| Group | 1 | 16 |
| Period | 1 | 2 |
| Block | s | p |
| Element category | Nonmetal | Nonmetal |
Physical properties
| Hydrogen | Oxygen | |
|---|---|---|
| Phase at STP | Gas | Gas |
| Density | 0.08988 g/cm3 | 1.429 g/cm3 |
| Atomic weight | 1.0079 u | 15.999 u |
| Melting point | 13.99 K -259.16 °C -434.488 °F | 54.36 K -218.79 °C -361.822 °F |
| Boiling point | 20.271 K -252.879 °C -423.1822 °F | 90.188 K -182.962 °C -297.3316 °F |
Atomic properties
| Hydrogen | Oxygen | |
|---|---|---|
| Electronegativity (Pauling Scale) | 2.2 | 3.44 |
| Electron affinity | 72.769 kJ/mol | 140.976 kJ/mol |
| Oxidation states | −1, +1 (an amphoteric oxide) | −2, −1, 0, +1, +2 () |
| Ionization energies |
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Electron configuration
| Hydrogen | Oxygen | |
|---|---|---|
| Shorthand configuration | 1s1 | [He] 2s2 2p4 |
| Full configuration | 1s1 | 1s2 2s2 2p4 |
| Electrons per shell | 1 | 2, 6 |
History
| Hydrogen | Oxygen | |
|---|---|---|
| Discovery | Henry Cavendish (1766) | Carl Wilhelm Scheele, Joseph Priestley (1774) |
| First isolation | Henry Cavendish (1766) | |
| Named by | Antoine Lavoisier (1783) | Antoine Lavoisier (1777) |