Neon-22 neutron excess from nitrogen-14 ($X_{22}=\frac{22}{14}{X}_{14},Y_e=\frac{1}{2}-\frac{X_{14}}{14}$)

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.