Sodium ($\mathrm{Na}$)

Sodium is the chemical element of atomic number eleven. Carbon-fusion channels in carbon burning include ${}^{12}\mathrm{C}+{}^{12}\mathrm{C}⟶{}^{23}\mathrm{Na}+p$, producing sodium-23 and a proton. Its abundance in expelled stellar material depends on later reactions and mixing, rather than on this one production channel alone.