Changes

The atomic weights are in the usual amu (atomic mass units). The "mass loss" column is obtained by subtracting the Daughter daughter mass from the Parent parent mass, and then subtracting 4.0026033 amu, which is the atomic weight of ⁴He₂, that is, an alpha particle. All atomic weights, by convention, include the electrons, so they are "atomic weights" and not "nuclear weights". But electrons are preserved, so it makes no difference when doing the subtractions. The Mass loss is then multiplied by the conversion factor of 931.494095 MeV per amu to get the expected potential energy converted to kinetic energy. The observed alpha emission energies (column 7) roughly match the converted potential energy loss (column 6). As discussed below, the alpha energies are smaller than the potential energy loss because the recoiling parent atom's energy is not considered.

Many of the alpha decays in the table are difficult to observe, and , for the purposes of this table, the atomic weights have only been calculated to 4 digits after the decimal point. This means that the mass defect is only accurate to about two significant digits. Aside from this inaccuracy, the observed alpha particle energy is less than the total energy released because the recoil of the parent nucleus takes some of the energy.