(Solved): 10.84 Except for nitrogen, the elements of Group \( 5 \mathrm{~A}(15) \) all form pentafluorides, ...

10.84 Except for nitrogen, the elements of Group \( 5 \mathrm{~A}(15) \) all form pentafluorides, and most form pentachlorides. The chlorine atoms of \( \mathrm{PCl}_{5} \) can be replaced with fluorine atoms one at a time to give, successively, \( \mathrm{PCl}_{4} \mathrm{~F}_{2} \mathrm{PCl}_{3} \mathrm{~F}_{2}, \ldots, \mathrm{PF}_{5} \). (a) Given the sizes of \( \mathrm{F} \) and \( \mathrm{Cl} \), would you expect the first two F substitutions to be at axial or equatorial positions? Explain. (b) Which of the five fluorinecontaining molecules have no dipole moment?