Changes

Now consider the hypothetical beta-plus decay of Argon-37 to Chlorine-37.  This Argon atom has 18 protons and 19 neutrons, and a nuclear mass of 36.9569019 amu.  The Chlorine atom has 17 protons and 20 neutrons, and a nuclear mass of 36.9565767 amu.  The beta-plus particle (positron) ejected by the nucleus weighs .00054858 amu.  There would be an overall mass ''increase'' of .00022343 amu.  This decay cannot happen.

Now consider the hypothetical beta-plus decay of Argon-37 to Chlorine-37.  This Argon atom has 18 protons and 19 neutrons, and a nuclear mass of 36.9569019 amu.  The Chlorine atom has 17 protons and 20 neutrons, and a nuclear mass of 36.9565767 amu.  The beta-plus particle (positron) ejected by the nucleus weighs .00054858 amu.  There would be an overall mass ''increase'' of .00022343 amu.  This decay cannot happen.

But suppose that, instead of releasing an electron and positron, the excess electron from the atom's electron cloud simply went down into the nucleus.  The nuclear transformation would be:

But suppose that, instead of releasing a positron, the excess electron from the atom's electron cloud simply went down into the nucleus.  The nuclear transformation would be:

:<math>\begin{align}

:<math>\begin{align}

p + \beta^- &\to n + \nu_e

p + \beta^- &\to n + \nu_e