Covalent Bonding 95
Name Date
Ch 8 Co
valent Bonding
Before You Read
ionic bond
octet rule
Chapter 4
Chapter 6
Chapter 8
Define the following terms.
Describe the structure of an atom.
Explain the following concepts: periodic trends and periodic
properties of elements.
Identify the ions, along with their charges, in the following ionic
compounds.
Li
2
S
KMnO
4
Al
2
O
3
Review
Vocabulary
095-112_Printer PDF 03/10/2007 02:41 PM Page 95
96 The Covalent Bond
Name Date
covalent bond
molecule
Lewis structure
sigma bond
pi bond
endothermic reaction
exothermic reaction
overlap
Covalent Bonding
Section 8.1 The Covalent Bond
Skim Section 1 of your text. Write three questions that come to
mind from reading the headings and the illustration captions.
1.
2.
3.
Use your text to define each term.
Define the following term.
New
Vocabulary
Academic
Vocabulary
Main Idea Details
095_112_CMC_SN_SE_878755.qxd 03/21/2007 11:21 AM Page 96
Printer PDF 2
Covalent Bonding 97
Name Date
Why do atoms
bond?
Use with page 240.
What is a
covalent bond?
Use with page 241.
Single Covalent
Bonds
Lewis Structure
of a Molecule
Problem 8.1, page 244.
Section 8.1 The Covalent Bond (continued)
Main Idea Details
Explain the octet rule by completing the following sentences.
The rule states that
. Although exceptions exist, the rule provides a useful frame-
work for understanding .
Complete the following sentences using words or phrases from
your text.
The force between two atoms is the result of
repulsion, nucleus-nucleus , and nucleus-electron
. At the point of , the
forces balance the forces. The most stable arrangement
of atoms exists at the point of , when the
atoms bond covalently and a forms.
Solve Read Example Problem 8.1 in your text.
You Try It
Problem
Draw the Lewis structure for hydrochloric acid, HCl.
1. Analyze the Problem
Write the electron-dot structures of each of the two component
atoms.
Known: H
,
Cl
Unknown: of HCl
Hydrogen, H, has only one valence electron. Chlorine, Cl, has
seven valence electrons. Cl needs one electron to complete its
octet.
2. Solve for the Unknown
Draw the electron-dot structure for each of the component atoms.
Then show the sharing of the pairs of electrons.
H
Cl 0 H—Cl
095-112_Printer PDF 03/12/2007 01:17 PM Page 97
98 The Covalent Bond
Name Date
Multiple Covalent
Bonds
Use with pages 245–246.
The Strength of
Covalent Bonds
Use with pages 246–247.
3. Evaluate the Answer
Each atom in the molecule has achieved a
configuration and thus is .
Identify each bond between the component atoms as sigma bonds
(single bonds), one sigma bond and one pi bond (double bonds), or
one sigma bond and two pi bonds (triple bonds).
HCCH
HCO
Explain the factors that control the strength of covalent bonds.
Define bond dissociation energy.
Section 8.1 The Covalent Bond (continued)
Main Idea Details
Explain how understanding covalent
bonding and the chemistry of compounds might help scientists increase food supplies.
R
EAL
-W
ORLD
C
ONNECTION
H
095-112_Printer PDF 03/10/2007 02:41 PM Page 98
Covalent Bonding 99
Name Date
oxyacid
The Covalent Bond
Section 8.2 Naming Molecules
Scan Section 2 of your text. Use the checklist below as a guide.
• Read all section titles.
• Read all boldfaced words.
• Read all tables and graphs.
• Read all formulas.
• Look at all figures and read the captions.
• Think about what you already know about the naming of
molecules.
Write three facts you discovered about the names and formulas of
covalent molecules.
1.
2.
3.
Use your text to define the following term.
New
Vocabulary
Main Idea Details
095-112_Printer PDF 03/10/2007 02:41 PM Page 99
100 Naming Molecules
Name Date
Naming Binary
Molecular
Compounds
Problem 8.2, page 249.
Section 8.2 Naming Molecules (continued)
Main Idea Details
Identify the prefixes for these three binary molecular compounds.
Ge
3
N
2
-germanium -nitride
C
2
Cl
4
-carbon -chloride
B
6
Si -boron silicide
Solve Read Example Problem 8.2 in your text.
You Try It
Problem
Name the compound N
2
O
3
.
1. Analyze the Problem
Known:
Unknown:
The formula reveals the elements present and the number of
atoms for each element. Only two elements are pr
esent, and
both are nonmetals, so the compound can be named according
to the rules for binary molecular compounds.
2. Solve for the Unknown
The first element present in the compound is , . The
second element is , . The root of this name is ,
so the second part of the name is . From the formula, two
atoms and three atoms make up a molecule
of the compound. The prefix for two is and prefix for three is
. The complete name for the compound is .
3. Evaluate the Answer
The name shows that a molecule of the
compound contains atoms and
atoms, which agrees with the chemical formula for the
compound, N
2
O
3
.
095-112_Printer PDF 03/10/2007 02:41 PM Page 100
Covalent Bonding 101
Name Date
Naming Acids
Use with page 250.
Writing Formulas
from Names
Use with pages 251–252.
Match the chemical formulas listed below with the correct acids.
HF sulfurous acid
HIO
4
hydrofluoric acid
H
2
SO
3
phosphoric acid
H
3
PO
4
hypochlorous acid
HC
2
H
3
O
2
periodic acid
H
2
CO
3
permanganic acid
HClO acetic acid
HMnO
4
carbonic acid
Write the chemical formula for the molecular compound names
given below. Use the flow chart in Figure 8.12 to help you deter-
mine the correct formulas.
dicarbon tetrabromide tetrasulfur tetranitride
arsenic pentafluoride arsenic acid
perchloric acid hydrocyanic acid
Section 8.2 Naming Molecules (continued)
Main Idea Details
Create questions and answers about naming molecules for
your own original quiz game. Include topics such as: prefixes and number of atoms;
formulas, common names, and molecular names for covalent binary compounds; and
formulas, common names, and molecular names for binary acids and oxyacids.
S
YNTHESIZE
095-112_Printer PDF 03/10/2007 02:41 PM Page 101
102 Molecular Structures
Name Date
structural formula
resonance
coordinate covalent
bond
Covalent Bonding
Section 8.3 Molecular Structures
Skim Section 3 of your text. Write three questions that come to
mind from reading the headings, illustration captions, and topics for
the example problems.
1.
2.
3.
Use your text to define each term.
New
Vocabulary
Main Idea Details
095-112_Printer PDF 03/10/2007 02:41 PM Page 102
Covalent Bonding 103
Name Date
Structural
Formulas
Use with pages 253–254.
Lewis Structure
for a Covalent
Compound with
Multiple Bonds
Problem 8.4, page 256.
Section 8.3 Molecular Structures (continued)
Main Idea Details
List the steps that should be used to determine Lewis structures.
1.
2.
3.
4.
Solve Read Example Problem 8.4 in your text.
You Try It
Problem
Draw the Lewis structure for FCHO.
1. Analyze the Problem
Known: the compound formula:
Unknown:
Carbon has less attraction for shared electrons, so it is the
central atom.
2. Solve for the Unknown
Find the total number of valence electrons and the number of
bonding pairs.
valence electr
ons/C atom valence electrons/F atom
1 valence electron/H atom valence electrons/O atom
valence electrons
available valence electrons/(2 electrons/pair)
available pairs
095-112_Printer PDF 03/10/2007 02:41 PM Page 103
104 Molecular Structures
Name Date
Lewis Structure
for a Polyatomic
Ion
Problem 8.5, page 257.
Section 8.3 Molecular Structures (continued)
Main Idea Details
Draw single bonds, which represent each, from
the carbon atom to each terminal atom, and place electron pairs
around the and atoms to give them stable
.
available pairs – pairs used = 0
Carbon does not have an octet, so one of the lone pairs on the
atom must be used to form a bond.
3. Evaluate the Answer
Both carbon and now have an octet, which satisfies the
octet rule.
Solve Read Example Problem 8.5 in your text.
You Try It
Problem
Draw the Lewis structure for the permanganate ion (MnO
4
–
).
1. Analyze the Problem
Known: the compound formula:
Unknown:
Manganese has less attraction for shared electrons, so it is the
central atom.
2. Solve for the Unknown
Find the total number of valence electr
ons and the number of
bonding pairs.
1 Mn atom ( valence electrons/Mn atom) O atoms
(6 valence electrons/O atom electron(s) from the
negative charge valence electrons
H—C—O
F
095-112_Printer PDF 03/10/2007 02:41 PM Page 104
Covalent Bonding 105
Name Date
Resonance
Structures
Use with page 258.
Exceptions to the
Octet Rule
Use with pages 258–259.
available valence electrons/(2 electrons/pair)
available pairs 1 electron
Draw single bonds, which represent an , from
the Mn atom to each O atom, and place electron pairs around
the O atoms to give them stable .
available pairs pairs used 0
No electron pairs remain available for the Mn atom, so the Lewis
structure for the permanganate ion is:
3. Evaluate the Answer
All atoms now have an octet, and the group of atoms has a net
charge of .
Explain resonance structures by completing the following sentences.
Each actual molecule or ion that undergoes behaves as
if it has only structure. Experimentally measured bond lengths
show that the bonds are to each other.
List three reasons for exceptions to the octet rule.
1.
2.
3.
Section 8.3 Molecular Structures (continued)
Main Idea Details
095-112_Printer PDF 03/10/2007 02:41 PM Page 105
106 Molecular Shapes
Name Date
VSEPR model
hybridization
Covalent Bonding
Section 8.4 Molecular Shapes
Scan Section 4 of your text. Use the checklist below as a guide.
• Read all section titles.
• Read all boldfaced words.
• Read all tables.
• Look at all pictures and read the captions.
• Think about what you already know about the shapes and
arrangements of atoms in covalent compounds.
Write three facts you discovered about the shapes covalent
compounds take.
1.
2.
3.
Use your text to define each term.
New
Vocabulary
Main Idea Details
095-112_Printer PDF 03/10/2007 02:41 PM Page 106
Covalent Bonding 107
Name Date
VSEPR Model
Use with pages 261–263.
Hybridization
Use with pages 262–263.
Match the molecular shapes listed below with their corresponding
bond angles.
trigonal planar 180°
trigonal pyramidal 120°
bent 109.5°
linear 107.3°
octahedral 104.5°
tetrahedral 90° (out of plane); 120° (in plane)
trigonal bipyramidal 90°
Label the hybrid orbitals in the figures below as sp, sp
2
,sp
3
sp
3
d,
or sp
3
d
2
.
Section 8.4 Molecular Shapes (continued)
Main Idea Details
sp
2
sp
3
d
Trigonal bipyramidal
Trigonal planar
095-112_Printer PDF 03/10/2007 02:41 PM Page 107
108 Molecular Shapes
Name Date
Find the Shape of
a Molecule
Problem 8.7, page 264.
Solve Read Example Problem 8.7 in your text.
You Try It
Problem
What is the shape of a SbI
5
molecule? Determine the bond angles,
and identify the type of hybrid orbitals that form the molecule’s bonds.
1. Analyze the Problem
Known: the compound formula:
Unknown:
The molecule contains one central antimony atom bonded to
iodine atoms.
2. Solve for the Unknown
Find the number of valence electrons and the number of electron
pairs.
1 Sb atom ( valence electrons/Sb atom) I atoms
( valence electrons/I atom) valence electrons
Three electron pairs exist on each iodine atom. This leaves
available valence electrons for bonding. available valence
electrons/(2 electrons/pair) available pairs
Draw the molecule’s Lewis structure. From this Lewis structure,
determine the molecular shape.
Section 8.4 Molecular Shapes (continued)
Main Idea Details
Lewis structure Molecular shape
The molecule’s shape is , with a bond
angle of in the horizontal plane, and a bond angle of
between the ver
tical and horizontal bonds. The bonds are made
up of hybrid orbitals.
3. Evaluate the Answer
Each iodine atom has an octet. The antimony atom has
electrons, which is allowed when a d orbital is hybridized.
095-112_Printer PDF 03/10/2007 02:41 PM Page 108
Covalent Bonding 109
Name Date
polar covalent bond
Covalent Bonding
Section 8.5 Electronegativity and Polarity
Scan Section 5 of your text. Use the checklist below as a guide.
• Read all section titles.
• Read all boldfaced words.
• Read all tables and charts.
• Look at all pictures and read the captions.
• Think about what you already know about the strengths and
distribution of charge in covalent bonds.
Write three facts you discovered about electrognegativity.
1.
2.
3.
Use your text to define the following term.
New
Vocabulary
Main Idea Details
095-112_Printer PDF 03/10/2007 02:41 PM Page 109
110 Electronegativity and Polarity
Name Date
Electron Affinity,
Electronegativity,
and Bond
Character
Use with pages 265–266.
Polar Covalent
Bonds
Use with pages 267–268.
Sequence the following elements from the least electronegative to
the most electronegative. Use Figure 8.20 for reference.
Au
Y
Ba
P
H
Te
O
I
Co
Draw the Lewis structure for each of the molecular compounds list-
ed below. Analyze the symmetry of the structure to determine
whether or not the compound is polar covalent or nonpolar covalent.
N
2
CO
2
CH
3
Cl
Section 8.5 Electronegativity and Polarity (continued)
Main Idea Details
095-112_Printer PDF 03/10/2007 02:41 PM Page 110
Covalent Bonding 111
Name Date
Properties of
Covalent
Compounds
Use with pages 269–270.
Covalent
Network Solids
Use with page 270.
Determine whether each of the properties listed below is charac-
teristic of ionic compounds, covalent compounds, nonpolar covalent
compounds, or polar covalent compounds.
low melting point
very soft solid
high boiling point
weak interaction between
formula units
solubility in oil
very hard solid
high melting point
solubility in water
easily vaporized
strong interaction between
formula units
Describe what the network solid for quartz (SiO
2
) molecules is like,
and how it has a tetrahedral structure similar to diamond structure.
Section 8.5 Electronegativity and Polarity (continued)
Main Idea Details
095-112_Printer PDF 03/10/2007 02:41 PM Page 111
112 Chapter Wrap-Up
Name Date
Review
After reading this chapter, list three key facts about covalent
bonding.
1.
2.
3.
Use this checklist to help you study.
Use this Science Notebook to study this chapter.
Study the vocabulary words and scientific definitions.
Review daily homework assignments.
Reread the chapter and review the tables, graphs, and
illustrations.
Review the Section Assessment questions at the end of
each section.
Look over the Study Guide at the end of the chapter.
Covalent Bonding Chapter Wrap-Up
Explain how covalent bonds in carbon
account for the vast number of carbon compounds, including those responsible for
living organisms.
R
EAL
-W
ORLD
C
ONNECTION
095-112_Printer PDF 03/10/2007 02:41 PM Page 112
