For sets of β+-decaying radioisotopes of the same element, the highest initial kinetic energy of the emitted positron falls off straightly with increasing atomic mass number <i>A</i>

Earlier, we had presented a systematization of [Formula: see text]-decaying nuclei, 1 where the interrelation between the decay half-life T and the highest initial kinetic energy [Formula: see text] of the positron at the instant it is emitted (if the neutrino energy is assumed to be zero) was transcribed through the formula [Formula: see text]. Herein, we reveal that the highest initial kinetic energy [Formula: see text] linearly decreases with respect to the increasing atomic mass number A for each of the given sets of [Formula: see text]-decaying radioisotopes of the same element. This, combined with the foregoing relationship, means a more stable [Formula: see text]-decaying nucleus, or the same, a longer decay half-life with respect to increasing A. All this, in turn, leads, as a first approximation, to an easily memorizable expression of the rate of change [Formula: see text] of the half-life versus the change [Formula: see text]A in the form of [Formula: see text]. Using this relationship, and putting aside possible anomalies, one can predict within an acceptable accuracy the half-lives of [Formula: see text]-decaying nuclei that could not be measured until now.