Question

Which is more ionic $\mathrm{NaCl}\mathrm{or}\mathrm{RbCl}$?

Answer 1

1. Sodium and Rubidium are the chemical elements that belong to the first group of the periodic table.
2. The atomic number of Sodium is $11$, and that of Rubidium is $37.$
3. Sodium and Rubidium both form cation.
4. We know that as we move top to down in the group the size of atom increases.
5. This increases the ionic radius as well.
6. The polarising power of cation is inversely proportional to the ionic radius.
7. This implies that for more ionic characters require less polarizing power.
8. The order of the size of the atom is as follows:${\mathrm{Na}}^{+}<{\mathrm{K}}^{+}<{\mathrm{Rb}}^{+}<{\mathrm{Cs}}^{+}<{\mathrm{Fr}}^{+}$
9. The cation of Rubidium is bigger than Sodium cation and so the ionic radius of Rubidium is more compared with Sodium.
10. Thus, Rubidium chloride$\left(\mathrm{RbCl}\right)$ is more ionic in nature as compared to Sodium chloride$\left(\mathrm{NaCl}\right)$