Chapter 10

What is the basic premise of the VSEPR model?

How does the VSEPR model explain the fact that the measured \(\mathrm{H}-\mathrm{O}-\mathrm{H}\) bond angle is 104.5 degrees, less than the predicted value of 109.5 degrees?

Draw the three possible arrangements of the fluorine atoms about the iodine atom in \(\mathrm{IF}_{3}\). Choose the shape predicted by VSEPR theory, and explain wby this arrangement is favored.

Draw the three possible arrangements of the fluorine atoms about the xenon atom in \(\mathrm{XeF}_{2}\). Choose the shape predicted by VSEPR theory, and explain wby this arrangement is favored.

Give an example of a nonpolar molecule that contains polar bonds. Show the polarity of the bonds with arrows, and show how these bond dipoles cancel.

Explain why \(\mathrm{SF}_{6}\) is nonpolar even though it contains polar S-F bonds.

Which species, \(\mathrm{O}_{2}\) or \(\mathrm{O}_{2}^{-}\), has the higher bond order? Explain your answer.

Give the valence-bond-theory description of how chemical bonds form.

Which atomic orbitals overlap to form the bonds in HI?

Why are hybrid orbitals needed to explain the bonding in \(\mathrm{CH}_{4} ?\)

Identify the hybrid orbitals used by boron in \(\mathrm{BCl}_{3}\) and in \(\mathrm{BCl}_{4}^{-},\) the ion formed from the reaction of \(\mathrm{BCl}_{3}\) and \(\mathrm{Cl}^{-} .\) Explain your choices.

Identify the hybrid orbitals used by antimony in \(\mathrm{SbCl}_{5}\) and in \(\mathrm{SbCl}_{6}^{-},\) the ion formed from the reaction of \(\mathrm{SbCl}_{5}\) and \(\mathrm{Cl}^{-}\). Explain your choices.

Explain why the molecular shape of HCl provides no information about the hybridization of the chlorine atom.

Make a table that shows the hybridization needed to explain bonds at angles of 180,120 , and 109.5 degrees.

Define a \(\sigma\) bond and a \(\pi\) bond. Show how \(p\) orbitals overlap in a \(\sigma\) bond and in a \(\pi\) bond.

Use valence bond theory to predict the planar shape of ethylene, \(\mathrm{C}_{2} \mathrm{H}_{4}\)

Draw the energy-level diagram for the bonding and antibonding molecular orbitals for \(\mathrm{H}_{2}\). Indicate their relative energies with respect to the 1 s atomic orbitals of isolated hydrogen atoms.

Draw two types of bonding molecular orbitals that can form from the overlap of \(2 p\) orbitals.

Compare and contrast the molecular orbital and ionic bonding descriptions of LiF.

Describe the bonding in molecular orbital terms for the delocalized \(\pi\) bond in \(\mathrm{O}_{3}\)

Give the bonded-atom lone-pair arrangement expected for a central atom that has (a) three bonded atoms and no lone pairs. (b) two bonded atoms and two lone pairs. (c) four bonded atoms and no lone pairs. (d) four bonded atoms and one lone pair.

Give the bonded-atom lone-pair arrangement expected for a central atom that has (a) two bonded atoms and one lone pair. (b) three bonded atoms and two lone pairs. (c) four bonded atoms and two lone pairs. (d) five bonded atoms and one lone pair.

Use the VSEPR model to predict the shape of the following species. (a) \(\mathrm{CF}_{4}\) (b) \(\mathrm{CS}_{2}\) (c) \(\mathrm{AsF}_{5}\) (d) \(\mathrm{F}_{2} \mathrm{CO}\) (e) \(\mathrm{NH}_{4}^{+}\)

Use the VSEPR model to predict the shape of the following species. (a) \(\mathrm{BeF}_{2}\) (b) \(\mathrm{SF}_{6}\) (c) \(\mathrm{SiH}_{4}\) (d) FCN (e) \(\mathrm{BeF}_{3}^{-}\)

Give the bonded-atom lonè-pair arrangement and the molecular shape of the following species. (a) \(\mathrm{SeO}_{2}\) (b) \(\mathrm{N}_{2} \mathrm{O}(\mathrm{N}\) is the central atom \()\) (c) \(\mathrm{H}_{3} \mathrm{O}^{+}\) (d) \(\mathrm{IF}_{5}\) (e) \(\mathrm{SCl}_{4}\)

In Give the bonded-atom lone-pair arrangement and the shape of the following species. (a) \(\mathrm{XeO}_{2}\) (b) \(\mathrm{I}_{3}^{-}\) (c) \(\mathrm{NO}_{2}^{-}\) (d) \(\mathrm{PCl}_{5}\) (e) \(\mathrm{AlCl}_{3}\)

Indicate which molecule of each pair has the smaller bond angles. Explain your answer. (a) \(\mathrm{BCl}_{3}\) or \(\mathrm{NCl}_{3}\) (b) \(\mathrm{OF}_{2}\) or \(\mathrm{SF}_{6}\)

Indicate which species of each pair has the smaller bond angles. Explain your answer. (a) \(\mathrm{SO}_{4}^{2-}\) or \(\mathrm{AlBr}_{3}\) (b) \(\mathrm{CCl}_{4}\) or \(\mathrm{BeI}_{2}\)

Indicate which species of each pair has the smaller bond angles. Explain your answer. (a) \(\mathrm{Cl}_{2} \mathrm{NH}\) or \(\mathrm{NH}_{4}^{+}\) (b) \(\mathrm{SF}_{2}\) or \(\mathrm{IF}_{4}^{-}\)

Indicate which species of each pair has the smaller bond angles. Explain your answer (a) \(\mathrm{BF}_{3}\) or \(\mathrm{AsCl}_{4}^{+}\) (b) \(\mathrm{CS}_{2}\) or \(\mathrm{AsCl}_{3}\)

Write a Lewis struicture for each of the following molecules. Indicate all of the bond angles as predicted by the VSEPR model. Deduce the skeleton structure from the way each formula is written. (a) \(\mathrm{H}_{3} \mathrm{CCCH}\) (b) \(\mathrm{Br}_{2} \mathrm{CCH}_{2}\) (c) \(\mathrm{H}_{3} \mathrm{CNH}_{2}\)

Write a Lewis structure for each of the following molecules. Indicate all of the bond angles as predicted by the VSEPR model. Deduce the skeleton structure from the way each formula is written. (a) \(\mathrm{ClC}(\mathrm{O}) \mathrm{NH}_{2}\) (oxygen bonded only to the carbon atom) (b) \(\mathrm{HOCH}_{2} \mathrm{CH}_{2} \mathrm{OH}\) (c) NCCN

Write a Lewis structure for each of the following species. Indicate all of the bond angles as predicted by the VSEPR model. Deduce the skeleton structure from the way each formula is written. (c) \(\mathrm{SCN}^{-}\) (a) \(\mathrm{SO}_{2}\) (b) \(\mathrm{ClO}_{3}^{-}\) (

I Predict the geometry of the following species: (a) \(\mathrm{SO}_{2}\) (b) \(\mathrm{BeCl}_{2}\) (c) \(\mathrm{SeCl}_{4}\) (d) \(\mathrm{PCl}_{5}\)

Use the VSEPR model to predict the bond angles around each central atom in the following Lewis structures (benzene rings are frequently pictured as hexagons, without the letter for the carbon atom at each vertex). Note that the drawings do not necessarily depict the bond angles correctly.

In Exercise 10.25 , the shapes of the following molecules were determined. State whether each molecule is polar or nonpolar. (a) \(\mathrm{CF}_{4}\) (b) \(\mathrm{CS}_{2}\) (c) \(\mathrm{AsF}_{5}\) (d) \(\mathrm{F}_{2} \mathrm{CO}\)

Indicate which molecules are polar and which are nonpolar. (a) \(\mathrm{SeO}_{2}\) (b) \(\mathrm{N}_{2} \mathrm{O}(\mathrm{N}\) is the central atom \()\) (c) \(\mathrm{SCl}_{4}\)

Indicate which molecules are polar and which are nonpolar. (a) \(\mathrm{SF}_{2}\) (b) \(\mathrm{PCl}_{5}\) (c) \(\mathrm{AlCl}_{3}\)

Indicate which of the following molecules are polar. Draw the molecular structure of each polar molecule, including the arrows that indicate the bond dipoles and the molecular dipole moment. (a) \(\mathrm{HCN}\) (b) \(\mathrm{I}_{2}\) (c) \(\mathrm{NO}\)

Indicate which of the following molecules are polar. Draw the molecular structure of each polar molecule, including the arrows that indicate the bond dipoles and the molecular dipole moment. (a) \(\mathrm{SiH}_{4}\) (b) \(\mathrm{PCl}_{3}\) (c) \(\mathrm{IF}_{5}\)

Indicate which of the following molecules are polar. Draw the molecular structure of each polar molecule, including the arrows that indicate the bond dipoles and the molecular dipole moment. (a) \(\mathrm{NF}_{3}\) (b) \(\mathrm{CBr}_{4}\) (c) \(\mathrm{BeI}_{2}\)

Indicate which of the following molecules are polar. Draw the molecular structure of each polar molecule, including the arrows that indicate the bond dipoles and the molecular dipole moment. (a) \(\mathrm{BCl}_{3}\) (b) \(\mathrm{OF}_{2}\) (c) \(\mathrm{SF}_{6}\)

Following are drawings of two derivatives of acetylene. Indicate whether each is polar or nonpolar, and explain your answer. (a) \(\mathrm{F}-\mathrm{C} \equiv \mathrm{C}-\mathrm{F}\) (b) \(\mathrm{H}-\mathrm{C} \equiv \mathrm{C}-\mathrm{F}\)

Identify the hybrid or atomic orbitals that form the bonds and hold lone pairs in any specific molecule. Identify the set of hybrid orbitals of a central atom that forms bonds with the following angles. (a) 120 degrees (b) 90 degrees (c) 180 degrees

Identify the hybrid or atomic orbitals that form the bonds and hold lone pairs in any specific molecule. Identify the hybridization of the central atom that has the bonded-atom lone- pair arrangement of (a) a tetrahedron. (b) a trigonal bipyramid. (c) an octahedron.

Identify the hybrid or atomic orbitals that form the bonds and hold lone pairs in any specific molecule. Identify the hybrid orbitals on the central atom that form the bonds in the following species. (a) \(\mathrm{CF}_{4}\) (b) \(\mathrm{SbCl}_{6}^{-}\) (c) \(\mathrm{AsF}_{5}\) (d) \(\mathrm{SiH}_{4}\) (e) \(\mathrm{NH}_{4}^{+}\)

Identify the hybrid orbitals on the central atom that form the bonds in the following species. (a) \(\mathrm{NF}_{3}\) (b) \(\mathrm{SCl}_{2}\) (c) \(\mathrm{H}_{3} \mathrm{O}^{+}\) (d) \(\mathrm{IF}_{5}\) (e) \(\mathrm{SCl}_{4}\)

Identify the hybrid orbitals on the central atom that form the \(\sigma\) bonds in the following species. (a) \(\mathrm{N}_{2} \mathrm{O}\) (b) \(\mathrm{Sn} \mathrm{Cl}_{2}\) (c) \(\mathrm{I}_{3}^{-}\) (d) \(\mathrm{SeO}_{2}\)

Identify the types of hybrid orbitals on the central atom that form the \(\sigma\) bonds in the following molecules. (a) \(\mathrm{ClF}_{3}\) (b) \(\mathrm{BBr}_{3}\) (c) \(\mathrm{BeF}_{2}\) (d) \(\mathrm{ONCl}\)

Identify the hybrid orbitals on the carbon atoms that form the \(\sigma\) bonds in the following species. (a) \(\mathrm{CO}_{3}^{2-}\) (b) \(\mathrm{CH}_{2} \mathrm{~F}_{2}\) (c) \(\mathrm{H}_{2} \mathrm{CO}\)