Which of the following is not isotopic pair? — Nuclear Chemistry and Radioactivity Chemistry Question

💡 Solution & Explanation

Let atomic number of A be $Z$. Then atomic numbers are B=$Z-2$, C=$Z-4$, D=$Z-3$, E=$Z-2$, F=$Z-4$, G=$Z-3$, H=$Z-5$. Isotopic pairs must share an atomic number. B and E ($Z-2$), C and F ($Z-4$), and D and G ($Z-3$) are isotopes. A ($Z$) and D ($Z-3$) are not. Therefore, correct answer is A.