Chapter 8

Determine the molecular shape, bond angle, and hybrid orbitals for each molecule. $$\mathrm{BF}_{3}$$

Determine the molecular shape, bond angle, and hybrid orbitals for each molecule. $$\mathrm{OCl}_{2}$$

Determine the molecular shape, bond angle, and hybrid orbitals for each molecule. $$\mathrm{BeF}_{2}$$

Determine the molecular shape, bond angle, and hybrid orbitals for each molecule. $$\mathrm{CF}_{4}$$

Challenge For a \(\mathrm{NH}_{4}^{+}\) ion, identify its molecular shape, bond angle, and hybrid orbitals.

Summarize the VSEPR bonding theory.

Define the term bond angle

Identify the type of hybrid orbitals present and bond angles for a molecule with a tetrahedral shape.

Compare the molecular shapes and hyrid orbitals of \(\mathrm{PF}_{3}\) and \(\mathrm{PF}_{5}\) molecules. Explain why their shapes differ.

List in a table, the Lewis structure, molecular shape, bond angle, and hybrid orbitals for molecules of \(\mathrm{CS}_{2}, \mathrm{CH}_{2} \mathrm{O}, \mathrm{H}_{2} \mathrm{OSe}, \mathrm{CC}_{2} \mathrm{F}_{2} \text { , and } \mathrm{NCl}_{3}\)

Summarize how electronegativity difference is related to bond character.

Describe a polar covalent bond.

Describe a polar molecule.

List three properties of a covalent compound in the solid phase.

Generalize Describe the general characteristics of covalent network solids.

Identify each molecule as polar or nonpolar: \(\mathrm{SCl}_{2}, \mathrm{CS}_{2},\) and \(\mathrm{CF}_{4}\)

Determine whether a compound made of hydrogen and sulfur atoms is polar or nonpolar.

Draw the Lewis structures for the molecules \(S F_{4}\) and \(S F_{6} .\) Analyze each structure to determine whether the molecule is polar or nonpolar.

What is the octet rule, and how is it used in covalent bonding?

Describe the formation of a covalent bond.

Describe the forces, both attractive and repulsive, that occur as two atoms move closer together.

Give the number of valence electrons in \(\mathrm{N}, \mathrm{As}, \mathrm{Br},\) and Se. Predict the number of covalent bonds needed for each of these elements to satisfy the octet rule.

In the molecules \(\mathrm{CO}, \mathrm{CO}_{2},\) and \(\mathrm{CH}_{2} \mathrm{O},\) which \(\mathrm{C}-\mathrm{O}\) bond is the shortest? Which \(\mathrm{C}-\mathrm{O}\) bond is the strongest?

Rank each of the molecules below in order of the shortest to the longest sulfur-oxygen bond length. $$ \text { a. } \mathrm{SO}_{2} \quad \text { b. } \mathrm{SO}_{3}^{2-} \quad \text { c. } \mathrm{SO}_{4}^{2-}$$

Explain the difference between sulfur hexafluoride and disulfur tetrafluoride.

Watches The quartz crystals used in watches are made of silicon dioxide. Explain how you use the name to determine the formula for silicon dioxide.

Name each molecule. $$\begin{array}{ll}{\text { a. } \mathrm{NF}_{3}} & {\text { c. } \mathrm{SO}_{3}} \\ {\text { b. } \mathrm{NO}} & {\text { d. } \mathrm{SiF}_{4}}\end{array}$$

Name each molecule. $$\begin{array}{ll}{\text { a. } \mathrm{SeO}_{2}} & {\text { c. } \mathrm{N}_{2} \mathrm{F}_{4}} \\ {\text { b. } \mathrm{SeO}_{3}} & {\text { d. } \mathrm{S}_{4} \mathrm{N}_{4}}\end{array}$$

Write the formula for each molecule $$\begin{array}{ll}{\text { a. sulfur difluoride }} & {\text { c. carbon tetrafluoride }} \\ {\text { b. silicon tetrachloride }} & {\text { d. sulfurous acid }}\end{array}$$

Write the formula for each molecule. $$\begin{array}{ll}{\text { a. silicon dioxide }} & {\text { c. chlorine trifluoride }} \\ {\text { b. bromous acid }} & {\text { d. hydrobromic acid }}\end{array}$$

What must you know in order to draw the Lewis structure for a molecule?

Doping Agent Material scientists are studying the properties of polymer plastics doped with AsF. Explain why the compound AsF \(_{5}\) is an exception to the octet rule.

Reducing Agent Boron trihydride \(\left(\mathrm{BH}_{3}\right)\) is used as reducing agent in organic chemistry. Explain why BH \(_{3}\) often forms coordinate covalent bonds with other molecules.

Antimony and chlorine can form antimony trichloride or antimony pentachloride. Explain how these two elements can form two different compounds.

Draw three resonance structures for the polyatomic ion \(\mathrm{CO}_{3}^{2-}\) .

Draw the Lewis structures for these molecules, each of which has a central atom that does not obey the octet rule. $$\begin{array}{ll}{\text { a. } \mathrm{PCl}_{5}} & {\text { c. ClF }_{5}} \\\ {\text { b. } \mathrm{BF}_{3}} & {\text { d. BeH }_{2}}\end{array}$$

Draw two resonance structures for the polyatomic ion \(\mathrm{HCO}_{2}-\) .

Draw the Lewis structure for a molecule of each of these compounds and ions. $$\begin{array}{ll}{\text { a. } \mathrm{H}_{2} \mathrm{S}} & {\text { c. } \mathrm{SO}_{2}} \\ {\text { b. } \mathrm{BF}_{4}-} & {\text { d. } \mathrm{SeCl}_{2}}\end{array}$$

Which elements in the list below are capable of forming molecules in which one of its atoms has an expanded octet? Explain your answer. $$\begin{array}{ll}{\text { a. } \mathrm{B}} & {\text { d. O }} \\ {\text { b. } C} & {\text { e. Se }} \\ {\text { c. } P}\end{array}$$

What is the maximum number of hybrid orbitals a carbon atom can form?

Predict the molecular shape of each molecule. a. COS \(\quad\) b. \(\mathrm{CF}_{2} \mathrm{Cl}_{2}\)

For each molecule listed below, predict its molecular shape and bond angle, and identify the hybrid orbitals. Drawing the Lewis structure might help you. $$\begin{array}{ll}{\text { a. } \mathrm{SCl}_{2}} & {\text { c. HOF }} \\\ {\text { b. } \mathrm{NH}_{2} \mathrm{Cl}} & {\text { d. } \mathrm{BF}_{3}}\end{array}$$

Describe electronegativity trends in the periodic table.

Explain the difference between nonpolar molecules and polar molecules.

Compare the location of bonding electrons in a polar covalent bond with those in a nonpolar covalent bond. Explain your answer

What is the difference between a covalent molecular solid and a covalent network solid? Do their physical properties differ? Explain your answer.

For each pair, indicate the more polar bond by circling the negative end of its dipole. $$ \begin{array}{l}{\text { a. } C-S, C-O} \\ {\text { b. } C-F, C-N} \\ {\text { c. } P-H, P-C 1}\end{array} $$

For each of the bonds listed, tell which atom is more negatively charged. $$\begin{array}{ll}{\text { a. } C-H} & {\text { c. } C-S} \\ {\text { b. } C-N} & {\text { d. } C-O}\end{array}$$

Predict which bond is the most polar $$\begin{array}{ll}{\text { a. } C-O} & {\text { c. } C-C l} \\ {\text { b. } S i-O} & {\text { d. } C-B r}\end{array}$$

Rank the bonds according to increasing polarity. $$\begin{array}{ll}{\text { a. } \mathrm{C}-\mathrm{H}} & {\text { d. } \mathrm{O}-\mathrm{H}} \\ {\text { b. } \mathrm{N}-\mathrm{H}} & {\text { e. } \mathrm{Cl}-\mathrm{H}} \\ {\text { c. } \mathrm{Si}-\mathrm{H}} & {\text { e. } \mathrm{Cl}-\mathrm{H}}\end{array}$$