= Neon-22 neutron excess from nitrogen-14
{title2=$X_{22}=\frac{22}{14}X_{14},\quad Y_e=\frac12-\frac{X_{14}}{14}$}
Two alpha captures and an intervening <beta-plus decay> turn each nitrogen-14 nucleus into neon-22, incorporating eight baryons from <helium> and converting one <proton> to a <neutron>. With no loss or dilution and nuclear <mass> defects neglected, a nitrogen-14 <mass> fraction $X_{14}$ therefore yields neon-22 <mass> fraction $(22/14)X_{14}$, not $X_{14}$. In otherwise symmetric carbon-oxygen matter this gives the displayed <electron fraction in stellar matter>. A final <neon> <mass> fraction and a pre-helium-burning metallicity must not silently be treated as identical.
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