The Group 5 A elements can form molecules or ions that involve three, five, or six covalent bonds; \(\mathrm{NH}_{3}, \mathrm{AsCl}_{5}\), and \(\mathrm{PF}_{6}^{-}\) are examples. Draw the Lewis structure for each of these substances, and predict the molecular structure and hybridization for each. Why doesn't \(\mathrm{NF}_{5}\) or \(\mathrm{NCl}_{6}^{-}\) form?

The Lewis structures, molecular structures, and hybridizations for NH₃, AsCl₅, and PF₆⁻ are as follows: 1. NH₃: Lewis structure: N with 3 single bonds to H atoms and 1 lone pair. Molecular structure: Trigonal pyramidal. Hybridization: sp³. 2. AsCl₅: Lewis structure: As with 5 single bonds to Cl atoms. Molecular structure: Trigonal bipyramidal. Hybridization: sp³d. 3. PF₆⁻: Lewis structure: P with 6 single bonds to F atoms. Molecular structure: Octahedral. Hybridization: sp³d². NF₅ and NCl₆⁻ do not form because nitrogen's 2p orbitals cannot accommodate enough electrons for the required number of bonds and due to steric hindrance from the larger Cl atoms.