Compare Elements
Add up to 4 elements to compare every property side by side. The link updates as you go — copy it to share this exact comparison.
H — HydrogenO — Oxygen
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| Property | H — Hydrogen | O — Oxygen |
|---|---|---|
| Atomic number | 1 | 8 |
| Atomic mass | 1.008 u | 15.999 u |
| Category | Nonmetal | Nonmetal |
| Group | 1 | 16 |
| Period | 1 | 2 |
| Block | s | p |
| Electron configuration | 1s1 | [He]2s2 2p4 |
| Oxidation states | +1, -1 | -2 |
| State at STP | gas | gas |
| Melting point | 13.81 K | 54.36 K |
| Boiling point | 20.28 K | 90.2 K |
| Density | 0.00008988 g/cm³ | 0.001429 g/cm³ |
| Electronegativity | 2.2 | 3.44 |
| First ionization energy | 13.598 eV | 13.618 eV |
| Electron affinity | 0.754 eV | 1.461 eV |
| Van der Waals radius | 120 pm | 152 pm |
| Discovered | 1766 | 1774 |