The number of orbitals associated with quantum numbers $\mathrm{n}=5,\mathrm{}{\mathrm{m}}_{\mathrm{s}}=+\frac{1}{2}$ is:

The difference between the radii of $3^{\mathrm{rd}}$ and $4^{\text{th }}$ orbits of ${\mathrm{Li}}_{}^{2+}$ is ${\mathrm{\Delta R}}_1$. The difference between the radii of $3^{\mathrm{rd}}$ and $4^{\text{th }}$ orbits of ${\mathrm{He}}^{+}$ is $\Delta {\mathrm{R}}_2.$ Ratio of  $\Delta {\mathrm{R}}_1:\Delta {\mathrm{R}}_2$ is :