| Quantity | Value | Units | Value | Units |
| Atomic number | 11 | |||
| Atomic mass | 22.98976928(2) | g mole-1 | ||
| Specific gravity | 0.9710 | g cm-3 | ||
| Mean excitation energy | 149.0 | eV | ||
| Minimum ionization | 1.639 | MeV g-1cm2 | 1.592 | MeV cm-1 |
| Nuclear collision length | 67.4 | g cm-2 | 69.46 | cm |
| Nuclear interaction length | 102.6 | g cm-2 | 105.6 | cm |
| Pion collision length | 93.4 | g cm-2 | 96.22 | cm |
| Pion interaction length | 132.2 | g cm-2 | 136.2 | cm |
| Radiation length | 27.74 | g cm-2 | 28.56 | cm |
| Critical energy | 51.38 | MeV (for e-) | 49.99 | MeV (for e+) |
| Molière radius | 11.45 | g cm-2 | 11.79 | cm |
| Plasma energy ℏωp | 19.64 | eV | ||
| Muon critical energy | 712. | GeV |