Problem 1
In which of the following molecular species does the central atom possess an octet of valence electrons? (a) \(\mathrm{BBr}_{2} \mathrm{F} ;(\mathrm{b}) \mathrm{OF}_{2} ;(\) (c) \(P H_{3} ;(d) C O_{2}\) (e) \(\mathrm{NF}_{3}\) (f) \(\left[\mathrm{PCl}_{4}\right]^{+} ;(\mathrm{g}) \mathrm{AsF}_{3} ;(\mathrm{h}) \mathrm{BF}_{3}\) (i) \(\mathrm{AlCl}_{3}\)
Problem 4
For each of the following, draw Lewis structures that are consistent with the central atom in each molecule obeying the octet rule: (a) \(\mathrm{H}_{2} \mathrm{O},(\mathrm{b}) \mathrm{NH}_{3}\) (c) \(\mathrm{AsF}_{3},(\mathrm{d}) \mathrm{SF}_{4}\)
Problem 6
How many single bonds may each of the (a) \(\mathrm{N}^{-}\) (b) \(\mathrm{B}^{-}\) and \((\mathrm{c}) \mathrm{C}^{-}\) centres form while obeying the octet rule?
Problem 8
The azide ion, \(\left[\mathrm{N}_{3}\right]^{-},\) is linear with equal \(\mathrm{N}-\mathrm{N}\) bond lengths. Give a description of the bonding in \(\left[\mathrm{N}_{3}\right]^{-}\) in terms of valence bond theory.
Problem 10
Write down the hybridization of the central atom in cach of the following species: (a) \(\mathrm{SiF}_{4} ;(\mathrm{b}) \mathrm{NH}_{3}\) (c) \(\left[\mathrm{NH}_{4}\right]^{+} ;(\mathrm{d}) \mathrm{BH}_{3} ;(\mathrm{e})\left[\mathrm{CoF}_{6}\right]^{3-} ;(\mathrm{f}) \mathrm{IF}_{3} ;(\mathrm{g}) \mathrm{H}_{2} \mathrm{S}\)
Problem 11
What hybridization scheme would you assign to the carbon atoms in cach of the following molecules? (a) \(\mathrm{CO}_{2} ;(\mathrm{b}) \mathrm{C}_{2} \mathrm{H}_{6} ;(\mathrm{c}) \mathrm{CH}_{2} \mathrm{Cl}_{2}\) (d) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{OH} ;\) (e) \(\mathrm{CH}_{3} \mathrm{CH}=\mathrm{CHCH}_{2} \mathrm{CH}_{3}\) \((\mathrm{f}) \mathrm{COCl}_{2} ;(\mathrm{g})\left[\mathrm{CO}_{3}\right]^{2-}\)
Problem 12
Explain why double bond character in a carbon-containing compound may be described in terms of an \(s p^{2}\) hybridization scheme but is incompatible with \(s p^{3}\) hybridization.
Problem 13
Consider the molecule \(\mathrm{CO}_{2}\). (a) Use VSEPR theory to rationalize its shape. (b) Draw resonance structures for \(\mathrm{CO}_{2}\) and indicate which structure will make the major contribution to the bonding. (c) Describe the bonding in terms of a hybridization scheme, including full descriptions of the formation of \(\sigma\) - and \(\pi\) -bonds.
Problem 16
Give appropriate hybridization schemes for the \(\mathbf{P}\) atom in each of the following species: (a) \(\mathrm{PF}_{5}\) (b) \(\left[\mathrm{PF}_{4}\right]^{+} ;(\mathrm{c})\left[\mathrm{PF}_{6}\right]^{-} ;(\mathrm{d}) \mathrm{PF}_{3} ;(\mathrm{e}) \mathrm{POCl}_{3}\) (f) PMes. For \(\left[\mathrm{PF}_{6}\right]\), draw Lewis structures that are consistent with \(\mathrm{P}\) obeying the octet rule, and with the \(P-F\) bonds being equivalent.
Problem 18
\(\left[\mathrm{BH}_{4}\right]\) is isoelectronic with \(\mathrm{CH}_{4} .\) By using a ligand group orbital approach, construct an MO diagram to show the interactions between \(B^{-}\) and four \(H\) atoms for form \(\left[\mathrm{BH}_{4}\right]^{-}\)
