Problem 56
Explain why the bond order of \(\mathrm{N}_{2}\) is greater than that of \(\mathrm{N}_{2}^{+}\), but the bond order of \(\mathrm{O}_{2}\) is less than that of \(\mathrm{O}_{2}^{+}\),
Problem 57
Compare the relative bond orders of the following species and indicate their magnetic properties (i.e. diamagnetic or paramagnetic): \(\mathrm{O}_{2}, \mathrm{O}_{2}^{+}, \mathrm{O}_{2}^{-}\) (superoxide ion) \(, \mathrm{O}_{2}^{2-}\) (peroxide ion).
Problem 58
Use molecular orbital theory to compare the relative stabilities of \(\mathrm{F}_{2}\) and \(\mathrm{F}_{2}^{+}\).
Problem 60
How does a delocalized molecular orbital differ from a molecular orbital such as that found in \(\mathrm{H}_{2}\) or \(\mathrm{C}_{2} \mathrm{H}_{4}\) ? What do you think are the minimum conditions (e.g. number of atoms and types of orbitals) for forming a delocalized molecular orbital?
Problem 62
Both ethylene \(\left(\mathrm{C}_{2} \mathrm{H}_{4}\right)\) and benzene \(\left(\mathrm{C}_{6} \mathrm{H}_{6}\right)\) contain the \(\mathrm{C}=\mathrm{C}\) bond. The reactivity of ethylene is greater than that of benzene. For example, ethylene readily reacts with molecular bromine, whereas benzene is normally quite inert toward molecular bromine and many other compounds. Explain this difference in reactivity.
Problem 64
Determine which of these molecules has a more delocalized orbital, and justify your choice. (Hint: Both molecules contain two benzene rings. In naphthalene, the two rings are fused together. In biphenyl, the two rings are joined by a single bond, around which the two rings can rotate.)
Problem 65
Nitryl fluoride \(\left(\mathrm{FNO}_{2}\right)\) is very reactive chemically. The fluorine and oxygen atoms are bonded to the nitrogen atom. (a) Write a Lewis structure for \(\mathrm{FNO}_{2}\). (b) Indicate the hybridization of the nitrogen atom. (c) Describe the bonding in terms of molecular orbital theory. Where would you expect delocalized molecular orbitals to form?
Problem 66
Describe the bonding in the nitrate ion \(\mathrm{NO}_{3}^{-}\) in terms of delocalized molecular orbitals.
Problem 67
What is the state of hybridization of the central \(\mathrm{O}\) atom in \(\mathrm{O}_{3} ?\) Describe the bonding in \(\mathrm{O}_{3}\) in terms of delocalized molecular orbitals.
Problem 68
Which of the following species is not likely to have a tetrahedral shape: (a) \(\mathrm{SiBr}_{4},(\mathrm{~b}) \mathrm{NF}_{4}^{+}\) (c) \(\mathrm{SF}_{4}\) (d) \(\mathrm{BeCl}_{4}^{2-}\) (e) \(\mathrm{BF}_{4}^{-}\) (f) \(\mathrm{AlCl}_{4}^{-} ?\)
