| 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 | 3.919 | MeV g-1cm2 | 0.2774 | 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 | 994.4 | cm |
| Pion interaction length | 80.3 | g cm-2 | 1134. | cm |
| Radiation length | 63.04 | g cm-2 | 890.4 | cm |
| Critical energy | 273.84 | MeV (for e-) | 267.33 | MeV (for e+) |
| Molière radius | 4.88 | g cm-2 | 68.95 | cm |
| Plasma energy ℏωp | 7.64 | eV | ||
| Muon critical energy | 3070. | GeV |