JEE Main · 2005 · 08 May 2005 · Offline · Chemical Kinetics

Knocking a single proton out of a nucleus removes one unit of charge and one unit of mass. Starting from ${}_{}^{}{}_{12}^{24}\mathrm{Mg}$, losing a proton drops the atomic number from $12$ to $11$ and the mass number from $24$ to $23$, written as ${}_{}^{}{}_{12}^{24}\mathrm{Mg}+\gamma \to {}_{}^{}{}_{11}^{23}\mathrm{Na}+{}_{}^{}{}_1^1\mathrm{p}$. Atomic number $11$ is sodium, so the nuclide formed is ${}_{}^{}{}_{11}^{23}\mathrm{Na}$.