91Ó°ÊÓ

Predict the shapes of the following molecules or ions: (a) \(\mathrm{O}_{3}\) (b) \(\mathrm{H}_{3} \mathrm{O}^{+}\) (c) \(\mathrm{XeF}_{2}\) (d) \(\mathrm{PF}_{6}^{-}\) (e) \(\mathrm{XeOF}_{4}\) (f) \(\mathrm{AlH}_{4}\) (g) \(\mathrm{BF}_{4}^{-}\) (h) \(\mathrm{SiCl}_{4}\) (i) \(\mathrm{ICl}_{4}^{-}\) (j) \(\mathrm{AlCl}_{3}\)

Identify the orbitals that overlap to form the \(\mathrm{C}-\mathrm{Cl}\) bonds and \(\mathrm{C}-\mathrm{H}\) bonds in \(\mathrm{CH}_{2} \mathrm{Cl}_{2}\).

Describe the bonding in propane, \(\mathrm{C}_{3} \mathrm{H}_{8}\), a fuel often used to heat rural homes and campers. Give the kinds of orbitals on each atom that overlap to form the \(\mathrm{C}-\mathrm{C}\) and \(\mathrm{C}-\mathrm{H}\) bonds.

Describe the hybridization of the carbon atom in formaldehyde, \(\mathrm{H}_{2} \mathrm{C}=\mathrm{O}\), and make a rough sketch of the molecule showing the orbitals involved in bonding.

Describe the hybridization of each carbon atom in lactic acid, a metabolite formed in tired muscles. Tell what kinds of orbitals on each atom overlap to form the carbon-carbon, carbonoxygen, and carbon-hydrogen bonds. Draw the overall shape of the molecule.

Describe the hybridization of the carbon atom in carbon dioxide, and make a rough sketch of the molecule showing its hybrid orbitals and \(\pi\) bonds.

Describe the hybridization of the carbon atom in the hydrogen cyanide molecule, \(\mathrm{H}-\mathrm{C} \equiv \mathrm{N}\), and make a rough sketch to show the hybrid orbitals it uses for bonding.

The dipole moment of \(\mathrm{HF}\) is \(\mu=1.83 \mathrm{D}\), and the bond length is \(92 \mathrm{pm}\). Calculate the percent ionic character of the \(\mathrm{H}-\mathrm{F}\) bond. Is HF more ionic or less ionic than \(\mathrm{HCl}\) (Worked Example 8.7)?

Construct an MO diagram for the \(\mathrm{He}_{2}{ }^{+}\) ion. What is its bond order? Is this ion likely to be stable?