| Quantity | Value | Units | Value | Units |
| Atomic number | 1 | |||
| Atomic mass | 1.008(7) | g mole-1 | ||
| Specific gravity | 0.07080 | g cm-3 | ||
| Mean excitation energy | 21.8 | eV | ||
| Minimum ionization | 4.034 | MeV g-1cm2 | 0.2856 | MeV cm-1 |
| Nuclear collision length | 42.8 | g cm-2 | 605.1 | cm |
| Nuclear interaction length | 52.0 | g cm-2 | 734.6 | cm |
| Pion collision length | 70.4 | g cm-2 | 994.5 | cm |
| Pion interaction length | 80.3 | g cm-2 | 1134. | cm |
| Radiation length | 63.05 | g cm-2 | 890.5 | cm |
| Critical energy | 278.03 | MeV (for e-) | 271.52 | MeV (for e+) |
| Molière radius | 4.81 | g cm-2 | 67.92 | cm |
| Plasma energy ℏωp | 7.64 | eV | ||
| Muon critical energy | 3102. | GeV | ||
| Melting point | 13.81 | K | -259.3 | C |
| Boiling point @ 1 atm | 20.28 | K | -252.9 | C |
| Index of refraction (Na D) | 1.112 |