Which of the following statements are true and false?

${\mathrm{S}}_1: {\mathrm{IE}}_1$ of $\mathrm{Sr}>\mathrm{Rb}$ but ${\mathrm{IE}}_2$ for $\mathrm{Rb}>\mathrm{Sr}$.

${\mathrm{S}}_2:$ The ionic radii of ${\mathrm{Li}}^{+}, {\mathrm{K}}^{+}, {\mathrm{Mg}}^{2+}$and ${\mathrm{Al}}^{3+}$ in $\mathrm{Å}$ are $0.76, 1.38, 0.720$ and $0.535,$ respectively.

${\mathrm{S}}_3:$ The negative value of electron gain enthalpy of $\mathrm{Cl}>\mathrm{F}$ because there is weak electron-electron repulsion in a bigger $3\mathrm{p}$ subshell of $\mathrm{Cl}$  as compared to compact $2\mathrm{p}$ subshell of $\mathrm{F}$.

${\mathrm{S}}_4:$ The second ionization energy of copper is less than potassium.