"Isosters" are defined as molecular species that contain the same number of atoms and the same total — Nuclear Chemistry and Radioactivity Chemistry Question

💡 Solution & Explanation

$N_2$ and $CO$ both have 2 atoms and 14 electrons. $CO_2$ and $N_2O$ both have 3 atoms and 22 electrons. $HCl$ and $F_2$ both have 2 atoms and 18 electrons. $O_2$ has 2 atoms and 16 electrons, while $O_3$ has 3 atoms and 24 electrons. Since $O_2$ and $O_3$ differ in both atom count and electron count, they are not isosters.