Write a Lewis structure for (a) \(\mathrm{XeF}_{3}{ }^{+}\) (b) \(\mathrm{PCl}_{4}^{+}\) (c) \(\mathrm{BrF}_{5}\) (d) \(\mathrm{HPO}_{4}^{2-}(\) no \(\mathrm{P}-\mathrm{H}\) or \(\mathrm{O}-\mathrm{O}\) bonds \()\)

To find the Lewis structure, first count the total number of valence electrons for each species: (a) \(\text{XeF}_{3}^{+}\) : Xe (8) + 3F (3x7) - 1(charge) = 28 electrons (b) \(\text{PCl}_{4}^{+}\) : P (5) + 4Cl (4x7) - 1(charge) = 34 electrons (c) \(\text{BrF}_{5}\) : Br (7) + 5F (5x7) = 42 electrons (d) \(\text{HPO}_{4}^{2-}\) : H (1) + P (5) + 4O (4x6) + 2(charge) = 32 electrons

Place the central atom (least electronegative element) in the center, and surround it with the other atoms. Distribute bonding electrons to form bonds between atoms, then assign the remaining electrons as lone pairs on surrounding atoms. (a) \(\text{XeF}_{3}^{+}\): \(\text{Xe}\) is at the center with 3 bonds to \(\text{F}\), remaining 10 valence electrons as 5 lone pairs on \(\text{Xe}\). (b) \(\text{PCl}_{4}^{+}\): \(\text{P}\) is at the center with 4 bonds to \(\text{Cl}\), remaining 2 valence electrons as 1 lone pair on \(\text{P}\). (c) \(\text{BrF}_{5}\): \(\text{Br}\) is at the center with 5 bonds to \(\text{F}\), remaining 2 valence electrons as 1 lone pair on \(\text{Br}\). (d) \(\text{HPO}_{4}^{2-}\): \(\text{P}\) is at the center with 4 bonds to \(\text{O}\), remaining 6 valence electrons as 3 lone pairs on 3 \(\text{O}\) atoms.

Make sure that each atom, except hydrogen, has an octet of electrons. In case there are resonance structures, draw molecules accordingly: Only \(\text{HPO}_{4}^{2-}\) displays resonance structures, including double bonds between the central \(\text{P}\) and three \(\text{O}\) atoms in alternating positions.

Indicate the correct charge for each species, and write the complete Lewis structure: (a) \(\text{XeF}_{3}^{+}\): [Xe(F)(F)(F)]\(^{+}\) (b) \(\text{PCl}_{4}^{+}\): [\(\text{P}(\text{Cl})_{4}\)]\(^{+}\) (c) \(\text{BrF}_{5}\): Br(F)\(_{5}\) (d) \(\text{HPO}_{4}^{2-}\): [H - O = P(=O)(-O)^{-}(-O)^{-}]\(^{2-}\) (Resonance structures can be formed by moving the double bond between the \(\text{P}\) and any of the other three \(\text{O}\) atoms.)