| Quantities of atomic physics | |
|---|---|
| Name | Symbol |
| Relative atomic mass | Ar |
| Half-life | T1/2 |
| Mass defect | Δ |
| Charge of the electron | e |
| Mass of an atom | ma |
| Mass of the neutron | mn |
| Mass of the proton | mp |
| Mass of the electron | me |
| Planck constant | h, ħ |
| Radius of the electron | re |