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Name ______________________________________ Date ____________ Class _______________________
Modern Chemistry • CHAPTER 6
HOMEWORK 6-1
(pp. 161–163)
VOCABULARY
Define.
1. chemical bond ______________________________________________________________________
__________________________________________________________________________________
2. covalent bond ______________________________________________________________________
__________________________________________________________________________________
3. ionic bonding ______________________________________________________________________
__________________________________________________________________________________
4. polar-covalent bond _________________________________________________________________
__________________________________________________________________________________
SKILL BUILDER
Use the electronegativity values to classify the bonds that would form between atoms of each of the
following elements.
Element
Electronegativity
Element
Electronegativity
Hydrogen (H)
2.1
Oxygen (O)
3.5
Sodium (Na)
0.9
Carbon (C)
2.5
Calcium (Ca)
1.0
Cobalt (Co)
1.8
Lithium (Li)
1.0
Nitrogen (N)
3.0
Bond
H and O
Type
Bond
N and O
H and C
Li and Ca
Na and Co
N and Ca
Li and N
Na and O
Ca and H
C and O
STANDARDIZED TEST PREP
Circle the letter of the best answer.
1. A large difference in electronegativity between two atoms in a bond results in
a. polar covalent bonding.
b. nonpolar covalent bonding.
c. ionic bonding.
d. repulsion between the two atoms.
2. Which of the following happens when atoms bond with each other?
a. The atoms increase in potential energy.
b. The potential energy of the compound is maximized.
c. Their electronegativity dramatically increases.
d. They create arrangements of matter that are more stable.
Modern Chemistry
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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Name ______________________________________ Date ____________ Class _______________________
Modern Chemistry • CHAPTER 6
HOMEWORK 6-2
(pp. 164–166)
VOCABULARY
Define.
1. molecule __________________________________________________________________________
__________________________________________________________________________________
2. molecular compound _________________________________________________________________
__________________________________________________________________________________
3. molecular formula ___________________________________________________________________
__________________________________________________________________________________
4. diatomic molecule ___________________________________________________________________
__________________________________________________________________________________
5. chemical formula ___________________________________________________________________
__________________________________________________________________________________
SKILL BUILDER
Complete each sentence.
1. Nature favors chemical bonding because _________________________________________________
_________________________________________________________________________________.
2. When atoms are drawn together by attractive forces, their potential energy ______________________.
3. Potential energy is at a minimum when __________________________________________________.
4. Atoms are drawn to each other because the electron-proton attraction is ________________________
_________________________________________________________________________________.
STANDARDIZED TEST PREP
Circle the letter of the best answer.
1. The molecular formula H2O indicates a molecule
a. with two atoms of oxygen bonded with one atom of hydrogen.
b. with two atoms of hydrogen bonded with one atom of oxygen.
c. that includes only ionic bonds.
d. that is diatomic.
2. Which statement is true?
a. A molecule can exist only if two of the same type of atom are bonded.
b. The strength of attraction between charged particles depends only on the type of atom involved
in the bond.
c. An atom of any element is a unit that can stand on its own.
d. The strength of attraction between charged particles depends on the distance between the atoms
involved in the bond.
Modern Chemistry
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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Name ______________________________________ Date ____________ Class _______________________
Modern Chemistry • CHAPTER 6
HOMEWORK 6-3
(pp. 167–169)
VOCABULARY
Write true or false for each statement.
1. The bond length is the distance between two bonded atoms at their maximum potential energy.
____________
2. The energy required to form a chemical bond between two neutral atoms is called bond energy.
____________
3. According to the octet rule, chemical compounds tend to form so that each atom has an octet of
electrons in its highest energy level. ____________
4. When the orbitals of the hydrogen atoms in a hydrogen molecule overlap, the electron density
between the nuclei decreases. ____________
SKILL BUILDING
On a separate sheet of paper, use Table 6-1 to create a graph comparing bond length to bond
energy. Plot bond length on the x-axis (in pm) and bond energy on the y-axis (in kJ/mol). Choose
ten bonds to portray on the graph.
y
x
What does your graph show about the relationship between bond length and bond energy?
STANDARDIZED TEST PREP
Circle the letter of the best answer.
1. Noble-gas atoms are able to exist independently in nature because
a. they are exceptions to the octet rule.
b. their bond energies are low compared to their bond lengths.
c. their electron configurations are more stable than those of other atoms.
d. they share electrons in overlapping orbitals with other noble-gas atoms.
2. Which statement is true?
a. As atoms are drawn together, the potential energy decreases.
b. Potential energy is at a maximum when attractive forces are balanced by repulsive forces.
c. The composition of an element is given by its molecular formula.
d. Hydrogen is the only element that bonds to achieve noble-gas configurations.
Modern Chemistry
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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Name ______________________________________ Date ____________ Class _______________________
Modern Chemistry • CHAPTER 6
HOMEWORK 6-4
(pp. 170–172)
VOCABULARY
Complete each sentence.
1. The ________________________________ notation shows only the valence electrons of an atom of a
particular element.
2. A lone pair is a pair of electrons that is _________________________________________________.
3. A single bond is a covalent bond produced by ___________________________________________.
4. a. A structural formula indicates ____________________________________________________.
b. It does not indicate _______________________________________________________________.
GRAPHIC ORGANIZER
Make a flow chart to show the steps in drawing the Lewis structure of a compound. Include at least
five steps. Then illustrate the steps on your flowchart as you draw the Lewis structure of CH4O.
STANDARDIZED TEST PREP
Circle the letter of the best answer.
1. The electron-dot notation of hydrogen is H•. This configuration proves
a. that a hydrogen atom has only one occupied energy level.
b. that hydrogen is a noble gas.
c. that the n = 1 level of a hydrogen atom contains a single electron.
d. both a and c.
2. Which of the following statements is true?
a. A pair of dots in electron-dot notation represents an electron pair of a lone atom in a compound.
b. Only valence electrons of a particular atom are shown in electron-dot notation.
c. A single bond is formed when a single electron brings two atoms together.
d. Covalent bond formation involves the electrons closest to the nuclei of the atoms.
Modern Chemistry
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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Name ______________________________________ Date ____________ Class _______________________
Modern Chemistry • CHAPTER 6
HOMEWORK 6-5
(pp. 172–175)
VOCABULARY
Define.
1. double bond ________________________________________________________________________
__________________________________________________________________________________
2. a. triple bond ______________________________________________________________________
b. How is a triple bond shown? _______________________________________________________
3. resonance _________________________________________________________________________
__________________________________________________________________________________
4. resonance structures _________________________________________________________________
__________________________________________________________________________________
GRAPHIC ORGANIZER
On a separate sheet of paper, use Table 6-2 on page 173 to create a graph comparing bond length to
bond energy. Plot bond length on the x-axis (in pm) and bond energy on the y-axis (in kJ/mol).
Depict all the bonds shown in the table on your graph.
y
x
What does your graph show about the relationship between bond length and bond energy? Which bonds
are stronger—single, double, or triple?
STANDARDIZED TEST PREP
Circle the letter of the best answer.
H
H
C
C
H
H . This Lewis structure shows that
1. The Lewis structure for C2H4 is
a. the bonds between carbon and hydrogen are double bonds.
b. each hydrogen atom has two valence electrons.
c. the bond between the carbon atoms is a double bond.
d. the bond energies of the carbon-hydrogen bonds are higher than the bond energy of the
carbon-carbon bond.
2. Which is the correct Lewis structure for HCl?
a. H Cl
b. H
Cl
c. H
Cl
d. H Cl
Modern Chemistry
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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Name ______________________________________ Date ____________ Class _______________________
Modern Chemistry • CHAPTER 6
HOMEWORK 6-6
(pp. 176–179)
VOCABULARY
Complete each sentence.
1. An ionic compound is ______________________________________________________________
_________________________________________________________________________________.
2. The chemical formula of an ionic compound represents ___________________________________
_________________________________________________________________________________.
3. A formula unit is __________________________________________________________________
_________________________________________________________________________________.
4. A crystal lattice is formed so that ______________________________________________________
_________________________________________________________________________________.
5. Lattice energy is the energy released when ______________________________________________
_________________________________________________________________________________.
SKILL BUILDER
On a separate sheet of paper, compare and contrast ionic and molecular compounds. Describe such
characteristics as the strength of forces of attraction, melting point, boiling point, hardness, and
solubility. Account for the differences between the two types of compounds.
STANDARDIZED TEST PREP
Circle the letter of the best answer.
1. Which statement is true of molecular compounds?
a. When dissolved in water, they conduct electricity.
b. They are hard, brittle substances.
c. Their lattice energies are positive rather than negative.
d. Some are completely gaseous at room temperature.
2. Which statement is true of ionic compounds?
a. The distances between the ions vary throughout the crystal.
b. All ionic crystals have the same structure.
c. The ions cannot move in the solid state.
d. All ionic compounds are able to dissolve in water.
Modern Chemistry
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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Name ______________________________________ Date ____________ Class _______________________
Modern Chemistry • CHAPTER 6
HOMEWORK 6-7
(pp. 179–180)
VOCABULARY
Write true or false for each statement.
1. A polyatomic ion is a group of covalently bonded atoms. ____________
2. NaCl is a molecular compound. _____________
3. Lattice energy is released when the ions in a crystal lattice are separated from each other.
____________
4. Ionic compounds are electrical conductors in their molten states. ____________
5. An ionic compound is composed of independent, neutral elements that can be isolated from
each other. _____________
6. The atoms in molecular compounds are held together by covalent bonds. ____________
SKILL BUILDER
Each of the compounds listed below is ionic or molecular. Based on the information given, write
ionic if the compound is more likely to be ionic than molecular. Write molecular if the compound is
more likely molecular than ionic.
1. Compound A is a gas at room temperature. __________________
2. Compound B breaks easily. ___________________
3. Compound C conducts electricity when dissolved in water. ___________________
4. Compound D has a value for lattice energy. ___________________
5. Compound E has a low melting point. ___________________
6. Compound F is not soluble in water. ___________________
7. The components of compound G are held together by electrical attraction. ___________________
STANDARDIZED TEST PREP
Circle the letter of the best answer.
1. Which statement is true?
a. Calculating lattice energies helps chemists compare bond strengths in ionic compounds.
b. Table salt is a molecular compound.
c. Na2Cl2 is a formula unit.
d. Ionic crystals form so that the potential energy of a compound is maximized.
2. Which statement is true?
a. Molecular formulas represent the simplest formulas for compounds.
b. The forces holding ions together in ionic bonds are relatively weak.
c. Intermolecular attractions that hold molecules together are stronger than ionic action.
d. A polyatomic ion with a shortage of electrons has a positive charge.
Modern Chemistry
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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CHAPTER 6 REVIEW
Chemical Bonding
MIXED REVIEW
SHORT ANSWER
Answer the following questions in the space provided.
1. Name the type of energy that is a measure of strength for each of the following types of bonds:
a. ionic bond
b. covalent bond
c. metallic bond
2. Use the electronegativity values shown in Figure 5-20, on page 151 of the text, to determine
whether each of the following bonds is nonpolar covalent, polar covalent, or ionic.
a. H—F
d. H—H
b. Na—Cl
e. H—C
c. H—O
f. H—N
3. How is a hydrogen bond different from an ionic or covalent bond?
4. H2S and H2O have similar structures and their central atoms belong to the same group. Yet H2S is a
gas at room temperature and H2O is a liquid. Use bonding principles to explain why this is true.
MODERN CHEMISTRY
HRW material copyrighted under notice appearing earlier in this work.
CHAPTER 6 MIXED REVIEW
51
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MIXED REVIEW continued
5. Why is a polar-covalent bond similar to an ionic bond?
6. Draw a Lewis structure for each of the following formulas. Determine whether the molecule is
polar or nonpolar.
a. H2S
CSC
—
—
H
H
C C
b. COCl2
CCl
C C
—
C C
—
—
C —O
CCl
C C
C — C
C C
c. PCl3
CCl —P — ClC
CClC
d. CH2O
—
H
52
—
H
a
C—O
CHAPTER 6 MIXED REVIEW
MODERN CHEMISTRY
HRW material copyrighted under notice appearing earlier in this work.