Organic chemistry 6th ed by brown foote iverson and anslyn pdf

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Organic Chemistry
SIXT H EDIT ION

William H. Brown
Beloit College

Christopher S. Foote
University of California, Los Angeles

Brent L. Iverson
University of Texas, Austin

Eric V. Anslyn
University of Texas, Austin
Chapter 29 was originally contributed by

Bruce M. Novak
North Carolina State University

Australia • Brazil • Japan • Korea • Mexico • Singapore • Spain • United Kingdom • United States

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


Organic Chemistry, Sixth Edition
William H. Brown, Christopher
S. Foote, Brent L. Iverson, Eric V. Anslyn
Executive Editor: Lisa Lockwood
Senior Developmental Editor: Sandra Kiselica
Assistant Editor: Elizabeth Woods
Editorial Assistant: Laura Bowen

© 2012, 2009 Brooks/Cole, Cengage Learning
ALL RIGHTS RESERVED. No part of this work covered by the copyright
herein may be reproduced, transmitted, stored, or used in any form
or by any means graphic, electronic, or mechanical, including but
not limited to photocopying, recording, scanning, digitizing, taping,
Web distribution, information networks, or information storage
and retrieval systems, except as permitted under Section 107 or 108
of the 1976 United States Copyright Act, without the prior written
permission of the publisher.

Senior Media Editor: Lisa Weber
Media Editor: Stephanie Van Camp
Senior Marketing Manager: Barb Bartoszek
Marketing Assistant: Julie Stefani
Marketing Communications Manager:
Linda Yip
Content Project Manager: Teresa L. Trego

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Cengage Learning Customer & Sales Support, 1-800-354-9706.
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Library of Congress Control Number: 2010939137

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ISBN-13: 978-0-8400-5498-2
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Printed in the United States of America
1 2 3 4 5 6 7 14 13 12 11 10

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


Organic Chemistry, Sixth Edition
William H. Brown, Christopher
S. Foote, Brent L. Iverson, Eric V. Anslyn
Executive Editor: Lisa Lockwood
Senior Developmental Editor: Sandra Kiselica
Assistant Editor: Elizabeth Woods

Editorial Assistant: Laura Bowen

© 2012, 2009 Brooks/Cole, Cengage Learning
ALL RIGHTS RESERVED. No part of this work covered by the copyright
herein may be reproduced, transmitted, stored, or used in any form
or by any means graphic, electronic, or mechanical, including but
not limited to photocopying, recording, scanning, digitizing, taping,
Web distribution, information networks, or information storage
and retrieval systems, except as permitted under Section 107 or 108
of the 1976 United States Copyright Act, without the prior written
permission of the publisher.

Senior Media Editor: Lisa Weber
Media Editor: Stephanie Van Camp
Senior Marketing Manager: Barb Bartoszek
Marketing Assistant: Julie Stefani
Marketing Communications Manager:
Linda Yip
Content Project Manager: Teresa L. Trego

For product information and technology assistance, contact us at
Cengage Learning Customer & Sales Support, 1-800-354-9706.
For permission to use material from this text or product,
submit all requests online at www.cengage.com/permissions.
Further permissions questions can be e-mailed to


Library of Congress Control Number: 2010939137

Design Director: Rob Hugel

Art Director: John Walker

ISBN-13: 978-0-8400-5498-2
ISBN-10: 0-8400-5498-X

Print Buyer: Judy Inouye
Rights Acquisitions Specialist:
Tom McDonough
Production Service: PreMediaGlobal
Text Designer: Ellen Pettengell
Photo Researcher: Bill Smith Group
Copy Editor: PreMediaGlobal
OWL producers: Stephen Battisti, Cindy
Stein, David Hart (Center for Educational
Software Development, University of
Massachusetts, Amherst)
Illustrator: Greg Gambino, PreMediaGlobal
Cover Designer: RHDG | Riezebos Holzbaur

Brooks/Cole
20 Davis Drive
Belmont, CA 94002-3098
USA
Cengage Learning is a leading provider of customized learning
solutions with office locations around the globe, including Singapore,
the United Kingdom, Australia, Mexico, Brazil, and Japan. Locate your
local office at www.cengage.com/global.
Cengage Learning products are represented in Canada by Nelson
Education, Ltd.
To learn more about Brooks/Cole, visit www.cengage.com/brookscole

Purchase any of our products at your local college store or at our
preferred online store www.cengagebrain.com.

Cover Image: © Corbis Images/Tobias
Bernhard
Compositor: PreMediaGlobal

Printed in the United States of America
1 2 3 4 5 6 7 14 13 12 11 10

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


Dedication
This Sixth Edition is dedicated to the memory of our dear friend and
colleague, Christopher Foote. Chris’ insights, encouragement, and
dedication to this project can never be replaced. His kind and nurturing
spirit lives on in all who are lucky enough to have known him.

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


About the Authors

WILLIAM H. BROWN is an Emeritus Professor of Chemistry at Beloit College,
where he has twice been named Teacher of the Year. His teaching responsibilities
included organic chemistry, advanced organic chemistry, and special topics in pharmacology and drug synthesis. He received his Ph.D. from Columbia University under
the direction of Gilbert Stork and did postdoctoral work at California Institute of

Technology and the University of Arizona.

CHRISTOPHER S. FOOTE received his B.S. from Yale University and his Ph.D.
from Harvard University. His scholarly credits include Sloan Fellow; Guggenheim
Fellow; ACS Baekland Award; ACS Cope Scholar; Southern California Section ACS
Tolman Medal; President, American Society for Photobiology; and Senior Editor,
Accounts of Chemical Research. He was a Professor of Chemistry at UCLA.

BRENT L. IVERSON received his B.S. from Stanford University and his Ph.D.
from the California Institute of Technology. He is a University Distinguished Teaching
Professor at The University of Texas, Austin as well as a respected researcher. Brent’s
research spans the interface of organic chemistry and molecular biology. His group
has developed several patented technologies, including an effective treatment for
anthrax.

ERIC V. ANSLYN is a University Distinguished Teaching Professor at The University of Texas at Austin. He earned his bachelor’s degree from California State
University, Northridge, his Ph.D. from the California Institute of Technology and did
postdoctoral work at Columbia University under the direction of Ronald Breslow.
Eric has won numerous teaching awards and his research focuses on the physical and
bioorganic chemistry of synthetic and natural receptors and catalysts.

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


Contents in Brief
1.
2.
3.
4.

5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.

Covalent Bonding and Shapes of Molecules
Alkanes and Cycloalkanes
Stereoisomerism and Chirality
Acids and Bases

Alkenes: Bonding, Nomenclature, and Properties
Reactions of Alkenes
Alkynes
Haloalkanes, Halogenation, and Radical Reactions
Nucleophilic Substitution and b-Elimination
Alcohols
Ethers, Epoxides, and Sulides
Infrared Spectroscopy
Nuclear Magnetic Resonance Spectroscopy
Mass Spectrometry
An Introduction to Organometallic Compounds
Aldehydes and Ketones
Carboxylic Acids
Functional Derivatives of Carboxylic Acids
Enolate Anions and Enamines
Dienes, Conjugated Systems, and Pericyclic Reactions
Benzene and the Concept of Aromaticity
Reactions of Benzene and Its Derivatives
Amines
Catalytic Carbon-Carbon Bond Formation
Carbohydrates
Lipids
Amino Acids and Proteins
Nucleic Acids
Organic Polymer Chemistry

Appendices:
1.
2.
3.

4.
5.
6.
7.
8.
9.
10.
11.

Thermodynamics and the Equilibrium Constant
Major Classes of Organic Acids
Bond Dissociation Enthalpies
Characteristic 1H-NMR Chemical Shifts
Characteristic 13C-NMR Chemical Shifts
Characteristic Infrared Absorption Frequencies
Electrostatic Potential Maps
Summary of Stereochemical Terms
Summary of the Rules of Nomenclature
Common Mistakes in Arrow Pushing
Organic Chemistry Road Maps

Glossary
Index
v
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


Contents in Brief
1.

2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.

Covalent Bonding and Shapes of Molecules

Alkanes and Cycloalkanes
Stereoisomerism and Chirality
Acids and Bases
Alkenes: Bonding, Nomenclature, and Properties
Reactions of Alkenes
Alkynes
Haloalkanes, Halogenation, and Radical Reactions
Nucleophilic Substitution and b-Elimination
Alcohols
Ethers, Epoxides, and Sulides
Infrared Spectroscopy
Nuclear Magnetic Resonance Spectroscopy
Mass Spectrometry
An Introduction to Organometallic Compounds
Aldehydes and Ketones
Carboxylic Acids
Functional Derivatives of Carboxylic Acids
Enolate Anions and Enamines
Dienes, Conjugated Systems, and Pericyclic Reactions
Benzene and the Concept of Aromaticity
Reactions of Benzene and Its Derivatives
Amines
Catalytic Carbon-Carbon Bond Formation
Carbohydrates
Lipids
Amino Acids and Proteins
Nucleic Acids
Organic Polymer Chemistry

Appendices:

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.

Thermodynamics and the Equilibrium Constant
Major Classes of Organic Acids
Bond Dissociation Enthalpies
Characteristic 1H-NMR Chemical Shifts
Characteristic 13C-NMR Chemical Shifts
Characteristic Infrared Absorption Frequencies
Electrostatic Potential Maps
Summary of Stereochemical Terms
Summary of the Rules of Nomenclature
Common Mistakes in Arrow Pushing
Organic Chemistry Road Maps

Glossary
Index
v
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Contents

Chapter 1 Covalent Bonding and Shapes of Molecules

1

1.1 Electronic Structure of Atoms 1
1.2 Lewis Model of Bonding 6
HOW TO Draw Lewis Structures from Condensed Structural Formulas

15

1.3 Functional Groups 16
1.4 Bond Angles and Shapes of Molecules 21
1.5 Polar and Nonpolar Molecules 24
CHEMICAL CONNECTIONS Fullerene—A New Form of Carbon

25

1.6 Quantum or Wave Mechanics 26
1.7 A Combined Valence Bond and Molecular Orbital Theory Approach to
Covalent Bonding

30

CONNECTIONS TO BIOLOGICAL CHEMISTRY Phosphoesters

37

1.8 Resonance 42
HOW TO Draw Curved Arrows and Push Electrons in Creating Contributing Structures 43

1.9 Molecular Orbitals for Delocalized Systems 48
1.10 Bond Lengths and Bond Strengths in Alkanes, Alkenes, and Alkynes 51
Summary 52

•

Problems 54

Chapter 2 Alkanes and Cycloalkanes

63

2.1 The Structure of Alkanes 63
2.2 Constitutional Isomerism in Alkanes 65
2.3 Nomenclature of Alkanes and the IUPAC System 67
2.4 Cycloalkanes 72
2.5 Conformations of Alkanes and Cycloalkanes 75
HOW TO Draw Alternative Chair Conformations of Cyclohexanes 86

2.6 Cis,Trans Isomerism in Cycloalkanes and Bicycloalkanes 88
HOW TO Convert Planar Cyclohexanes to Chair Cyclohexanes
CHEMICAL CONNECTIONS The Poisonous Puffer Fish

90

95

2.7 Physical Properties of Alkanes and Cycloalkanes 96
2.8 Reactions of Alkanes 99
2.9 Sources and Importance of Alkanes 101

vi
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


Contents

Chapter 1 Covalent Bonding and Shapes of Molecules

1

1.1 Electronic Structure of Atoms 1
1.2 Lewis Model of Bonding 6
HOW TO Draw Lewis Structures from Condensed Structural Formulas

15

1.3 Functional Groups 16
1.4 Bond Angles and Shapes of Molecules 21
1.5 Polar and Nonpolar Molecules 24
CHEMICAL CONNECTIONS Fullerene—A New Form of Carbon

25

1.6 Quantum or Wave Mechanics 26
1.7 A Combined Valence Bond and Molecular Orbital Theory Approach to

Covalent Bonding

30

CONNECTIONS TO BIOLOGICAL CHEMISTRY Phosphoesters

37

1.8 Resonance 42
HOW TO Draw Curved Arrows and Push Electrons in Creating Contributing Structures 43

1.9 Molecular Orbitals for Delocalized Systems 48
1.10 Bond Lengths and Bond Strengths in Alkanes, Alkenes, and Alkynes 51
Summary 52

•

Problems 54

Chapter 2 Alkanes and Cycloalkanes

63

2.1 The Structure of Alkanes 63
2.2 Constitutional Isomerism in Alkanes 65
2.3 Nomenclature of Alkanes and the IUPAC System 67
2.4 Cycloalkanes 72
2.5 Conformations of Alkanes and Cycloalkanes 75
HOW TO Draw Alternative Chair Conformations of Cyclohexanes 86

2.6 Cis,Trans Isomerism in Cycloalkanes and Bicycloalkanes 88
HOW TO Convert Planar Cyclohexanes to Chair Cyclohexanes
CHEMICAL CONNECTIONS The Poisonous Puffer Fish

90

95

2.7 Physical Properties of Alkanes and Cycloalkanes 96
2.8 Reactions of Alkanes 99
2.9 Sources and Importance of Alkanes 101

vi
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


Contents

Chapter 1 Covalent Bonding and Shapes of Molecules

1

1.1 Electronic Structure of Atoms 1
1.2 Lewis Model of Bonding 6
HOW TO Draw Lewis Structures from Condensed Structural Formulas

15

1.3 Functional Groups 16

1.4 Bond Angles and Shapes of Molecules 21
1.5 Polar and Nonpolar Molecules 24
CHEMICAL CONNECTIONS Fullerene—A New Form of Carbon

25

1.6 Quantum or Wave Mechanics 26
1.7 A Combined Valence Bond and Molecular Orbital Theory Approach to
Covalent Bonding

30

CONNECTIONS TO BIOLOGICAL CHEMISTRY Phosphoesters

37

1.8 Resonance 42
HOW TO Draw Curved Arrows and Push Electrons in Creating Contributing Structures 43

1.9 Molecular Orbitals for Delocalized Systems 48
1.10 Bond Lengths and Bond Strengths in Alkanes, Alkenes, and Alkynes 51
Summary 52

•

Problems 54

Chapter 2 Alkanes and Cycloalkanes

63

2.1 The Structure of Alkanes 63
2.2 Constitutional Isomerism in Alkanes 65
2.3 Nomenclature of Alkanes and the IUPAC System 67
2.4 Cycloalkanes 72
2.5 Conformations of Alkanes and Cycloalkanes 75
HOW TO Draw Alternative Chair Conformations of Cyclohexanes 86

2.6 Cis,Trans Isomerism in Cycloalkanes and Bicycloalkanes 88
HOW TO Convert Planar Cyclohexanes to Chair Cyclohexanes
CHEMICAL CONNECTIONS The Poisonous Puffer Fish

90

95

2.7 Physical Properties of Alkanes and Cycloalkanes 96
2.8 Reactions of Alkanes 99
2.9 Sources and Importance of Alkanes 101

vi
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


Outline
1.1
1.2

▲

Chapter 1

Lewis Model of Bonding

How To Draw Lewis Structures from
Condensed Structural Formulas

1.3
1.4

Covalent Bonding
and Shapes of
Molecules

Electronic Structure of Atoms

1.5

Functional Groups
Bond Angles and Shapes
of Molecules
Polar and Nonpolar Molecules
Chemical Connections:
Fullerene—A New Form
of Carbon

1.6
1.7

Quantum or Wave Mechanics

1.8

Resonance

A Combined Valence Bond
and Molecular Orbital Theory
Approach to Covalent Bonding

▲

How To Draw Curved Arrows
and Push Electrons in Creating
Contributing Structures

1.9

Molecular Orbitals for
Delocalized Systems

1.10 Bond Lengths and Bond
Strengths in Alkanes,
Alkenes, and Alkynes

© Cengage Learning/Charles D. Winters

A model of the structure of
diamond, one form of pure
carbon. Each carbon is bonded

to four other carbons at the
corners of a tetrahedron. Inset:
a model of fullerene (C60). See the
box “Fullerene—A New Form
of Carbon.”

A

ccording to the simplest definition, organic chemistry is the study of the
compounds of carbon. Perhaps its most remarkable feature is that most
organic compounds consist of carbon and only a few other elements—chiefly,
hydrogen, oxygen, and nitrogen. Chemists have discovered or made well over ten
million compounds composed of carbon and these three other elements. Organic
compounds are everywhere around us—in our foods, lavors, and fragrances; in our
medicines, toiletries, and cosmetics; in our plastics, ilms, ibers, and resins; in
our paints and varnishes; in our glues and adhesives; in our fuels and lubricants;
and, of course, in our bodies and those of all living things.
Let us begin our study of organic chemistry with a review of how the elements
of C, H, O, and N combine by sharing electron pairs to form bonds, and ultimately
molecules. There is a great deal of material in this chapter, but you have encountered much of it in your previous chemistry courses. However, because all subsequent chapters in this book use this material, it is essential that you understand it
and can use it luently.

1.1 Electronic Structure of Atoms
An atom contains a small, dense nucleus made of neutrons and positively charged
protons. Most of the mass of an atom is contained in its nucleus. The nucleus is
surrounded by an extranuclear space containing negatively charged electrons. The
nucleus of an atom has a diameter of 10214 to 10215 meters (m). The extranuclear
space where its electrons are found is a much larger volume with a diameter of
approximately 10–10 m (Figure 1.1).

Online homework for this
chapter may be assigned in OWL
for Organic Chemistry, an online
learning assessment tool.

1
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


Outline
1.1
1.2

▲

Chapter 1

Lewis Model of Bonding

How To Draw Lewis Structures from
Condensed Structural Formulas

1.3
1.4

Covalent Bonding
and Shapes of
Molecules

Electronic Structure of Atoms

1.5

Functional Groups
Bond Angles and Shapes
of Molecules
Polar and Nonpolar Molecules
Chemical Connections:
Fullerene—A New Form
of Carbon

1.6
1.7

Quantum or Wave Mechanics

1.8

Resonance

A Combined Valence Bond
and Molecular Orbital Theory
Approach to Covalent Bonding

▲

How To Draw Curved Arrows
and Push Electrons in Creating
Contributing Structures

1.9

Molecular Orbitals for
Delocalized Systems

1.10 Bond Lengths and Bond
Strengths in Alkanes,
Alkenes, and Alkynes

© Cengage Learning/Charles D. Winters

A model of the structure of
diamond, one form of pure
carbon. Each carbon is bonded
to four other carbons at the
corners of a tetrahedron. Inset:
a model of fullerene (C60). See the
box “Fullerene—A New Form
of Carbon.”

A

ccording to the simplest definition, organic chemistry is the study of the
compounds of carbon. Perhaps its most remarkable feature is that most
organic compounds consist of carbon and only a few other elements—chiefly,
hydrogen, oxygen, and nitrogen. Chemists have discovered or made well over ten
million compounds composed of carbon and these three other elements. Organic
compounds are everywhere around us—in our foods, lavors, and fragrances; in our
medicines, toiletries, and cosmetics; in our plastics, ilms, ibers, and resins; in

our paints and varnishes; in our glues and adhesives; in our fuels and lubricants;
and, of course, in our bodies and those of all living things.
Let us begin our study of organic chemistry with a review of how the elements
of C, H, O, and N combine by sharing electron pairs to form bonds, and ultimately
molecules. There is a great deal of material in this chapter, but you have encountered much of it in your previous chemistry courses. However, because all subsequent chapters in this book use this material, it is essential that you understand it
and can use it luently.

1.1 Electronic Structure of Atoms
An atom contains a small, dense nucleus made of neutrons and positively charged
protons. Most of the mass of an atom is contained in its nucleus. The nucleus is
surrounded by an extranuclear space containing negatively charged electrons. The
nucleus of an atom has a diameter of 10214 to 10215 meters (m). The extranuclear
space where its electrons are found is a much larger volume with a diameter of
approximately 10–10 m (Figure 1.1).

Online homework for this
chapter may be assigned in OWL
for Organic Chemistry, an online
learning assessment tool.

1
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
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C. Lewis Dot Structures

Valence electrons
Electrons in the valence (outermost)
shell of an atom.

Valence shell
The outermost occupied electron
shell of an atom.

© Bettmann/CORBIS

Lewis dot structure
The symbol of an element
surrounded by a number of dots
equal to the number of electrons in
the valence shell of the atom.

When discussing the physical and chemical properties of an element, chemists
often focus on the electrons in the outermost shell of the atom because these electrons are involved in the formation of chemical bonds and in chemical reactions.
Carbon, for example, with the ground-state electron coniguration 1s 2 2s 2 2p 2, has
four outer-shell electrons. Outer-shell electrons are called valence electrons, and
the energy level in which they are found is called the valence shell. To show the
outermost electrons of an atom, we commonly use a representation called a Lewis
dot structure, after the American chemist Gilbert N. Lewis (1875–1946) who
devised this notation. A Lewis dot structure shows the symbol of the element surrounded by a number of dots equal to the number of electrons in the outer shell
of an atom of that element. In Lewis dot structures, the atomic symbol represents
the core; that is, the nucleus and all inner shell electrons. Table 1.4 shows Lewis dot
structures for the irst 18 elements of the Periodic Table.
TThe noble gases helium and neon have illed valence shells. The valence shell of
helium is illed with two electrons; that of neon is illed with eight electrons. Neon
and argon have in common an electron coniguration in which the s and p orbitals
of their valence shells are illed with eight electrons. The valence shells of all other
elements shown in Table 1.4 contain fewer than eight electrons.
For C, N, O, and F in period 2 of the Periodic Table, the valence electrons belong to the second shell. With eight electrons, this shell is completely illed. For Si, P,
S, and Cl in period 3 of the Periodic Table, the valence electrons belong to the third

shell. This shell is only partially illed with eight electrons; the 3s and 3p orbitals are
fully occupied, but the ive 3d orbitals can accommodate an additional ten electrons.
Lewis Dot Structures for
Elements 1–18*

Table 1.4

1A

Gilbert N. Lewis (1875–1946)
introduced the theory of the electron
pair that extended our understanding
of covalent bonding and of the
concept of acids and bases. It is in
his honor that we often refer to an
“electron dot” structure as a Lewis
structure.

2A

3A

4A

5A

6A

7A

H

8A
He

Li

Be

B

C

N

O

F

Ne

Na

Mg

Al

Si

P

S

Cl

Ar

*These dots represent electrons from the valence
shell. They are arranged as pairs or single electrons in
accordance with Hund’s rule.

1.2 Lewis Model of Bonding

Octet rule
Group 1A–7A elements react to
achieve an outer shell of eight
valence electrons.

In 1916, Lewis devised a beautifully simple model that uniied many of the observations about chemical bonding and reactions of the elements. He pointed out that the
chemical inertness of the noble gases indicates a high degree of stability of the electron
conigurations of these elements: helium with a valence shell of two electrons (1s 2),
neon with a valence shell of eight electrons (2s2 2p 6), and argon with a valence shell of
eight electrons (3s 2 3p 6). The tendency of atoms to react in ways that achieve an outer
shell of eight valence electrons is particularly common among second-row elements of
Groups 1A–7A (the main-group elements) and is given the special name octet rule.

Example 1.2
Show how the loss of an electron from a sodium atom leads to a stable octet.
Solution

The ground-state electron conigurations for Na and Na1 are:
Na (11 electrons): 1s 2 2s 2 2p 6 3s 1
Na1 (10 electrons): 1s 2 2s 2 2p 6
6

Chapter 1

Covalent Bonding and Shapes of Molecules

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Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


How To

Draw Lewis Structures from Condensed
Structural Formulas

Drawing Lewis structures from condensed structural formulas is a survival skill for
organic chemistry students. There are three steps you should follow to draw a correct structure.
1. From a structural formula, obtain information about which atoms are bonded
to each other in a molecule. Connect all of the appropriate atoms with single
bonds (single lines) irst.
Example: CH3CH2CH2COOCH3
H

H

H

O
H

H9C9C9C9C
H

H

H

O9C9H
H

Comment: The dificult part of this structure is deciding how to
arrange the two oxygen atoms. Using the arrangement shown will
produce a stable structure with illed valences for all of the atoms
after you have completed Step 3 below. With practice you will begin to recognize common functional groups (Section 1.3) such as
the carboxylic ester group (!COOCH3 in this example). If you
are unsure, you must draw the different possibilities you are considering, and upon completing the structure, determine which
one produces the stable structure with the maximum number of
illed valence shells around the atoms.

2. Determine how many electrons have been used for the bonds and how many
remain. Add all of the additional valence electrons for each atom that does not
already have a illed valence shell due to the single bonds. Remember to assign one electron to each atom taking part in a single bond for the purpose of
counting valence electrons around atoms. Make sure to keep track of any formal
charges that may be present in the condensed structural formula (the present
example has none).
H

H

H

O
H

H9C9C9C9C
H

H

H

O9C9H
H

Comment: Recall that each neutral carbon atom has four valence electrons, and each neutral oxygen atom has six valence
electrons. After taking into account all of the single bonds in
the molecule, the carbon atom bonded to both oxygen atoms
has a single electron left over (4 total electrons 2 3 single bonds
5 1 electron left over), the oxygen atom bonded only to one
carbon atom has ive electrons left over (6 total electrons 2 1
single bond 5 5 electrons left over), and the other oxygen atom
has four electrons left over (6 total electrons 2 2 single bonds
5 4 electrons left over).

3. Add multiple bonds to eliminate unpaired electrons. Draw the remaining
nonbonding electrons as lone pairs.
H

H

H

H9C9C9C9C
H

H

H

O
H

Comment: The only unpaired electrons were on carbon and
oxygen, leading to one new bond being formed.

O9C9H
H

The Lewis structure is now complete. The good news is that drawing Lewis
structures will get easier with practice.

halogens have one bond and three lone pairs. When counting bonds for this
analysis, double bonds count as two bonds, and triple bonds count as three bonds.
For atoms with a formal charge, the number of bonds and lone pairs is altered.
For example, positively charged nitrogen has four bonds and no lone pairs, positively charged oxygen has three bonds and one lone pair, and positively charged
carbon has three bonds and no lone pairs (carbon has an unilled valence shell).

1.2

Lewis Model of Bonding

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15


How To

Draw Lewis Structures from Condensed
Structural Formulas

Drawing Lewis structures from condensed structural formulas is a survival skill for
organic chemistry students. There are three steps you should follow to draw a correct structure.
1. From a structural formula, obtain information about which atoms are bonded
to each other in a molecule. Connect all of the appropriate atoms with single
bonds (single lines) irst.
Example: CH3CH2CH2COOCH3
H

H

H

O
H

H9C9C9C9C
H

H

H

O9C9H
H

Comment: The dificult part of this structure is deciding how to
arrange the two oxygen atoms. Using the arrangement shown will
produce a stable structure with illed valences for all of the atoms
after you have completed Step 3 below. With practice you will begin to recognize common functional groups (Section 1.3) such as
the carboxylic ester group (!COOCH3 in this example). If you
are unsure, you must draw the different possibilities you are considering, and upon completing the structure, determine which
one produces the stable structure with the maximum number of
illed valence shells around the atoms.

2. Determine how many electrons have been used for the bonds and how many
remain. Add all of the additional valence electrons for each atom that does not
already have a illed valence shell due to the single bonds. Remember to assign one electron to each atom taking part in a single bond for the purpose of
counting valence electrons around atoms. Make sure to keep track of any formal
charges that may be present in the condensed structural formula (the present
example has none).
H

H

H

O
H

H9C9C9C9C
H

H

H

O9C9H
H

Comment: Recall that each neutral carbon atom has four valence electrons, and each neutral oxygen atom has six valence
electrons. After taking into account all of the single bonds in
the molecule, the carbon atom bonded to both oxygen atoms
has a single electron left over (4 total electrons 2 3 single bonds
5 1 electron left over), the oxygen atom bonded only to one
carbon atom has ive electrons left over (6 total electrons 2 1
single bond 5 5 electrons left over), and the other oxygen atom
has four electrons left over (6 total electrons 2 2 single bonds
5 4 electrons left over).

3. Add multiple bonds to eliminate unpaired electrons. Draw the remaining
nonbonding electrons as lone pairs.
H

H

H

H9C9C9C9C
H

H

H

O
H

Comment: The only unpaired electrons were on carbon and
oxygen, leading to one new bond being formed.

O9C9H
H

The Lewis structure is now complete. The good news is that drawing Lewis
structures will get easier with practice.

halogens have one bond and three lone pairs. When counting bonds for this
analysis, double bonds count as two bonds, and triple bonds count as three bonds.
For atoms with a formal charge, the number of bonds and lone pairs is altered.
For example, positively charged nitrogen has four bonds and no lone pairs, positively charged oxygen has three bonds and one lone pair, and positively charged
carbon has three bonds and no lone pairs (carbon has an unilled valence shell).

1.2

Lewis Model of Bonding

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15


Negatively charged carbon has three bonds and one lone pair, negatively charged
nitrogen has two bonds and two lone pairs, and negatively charged oxygen has one
bond and three lone pairs.
The guidelines for formal charge can be generalized. Any atom with an octet
plus one bond more than its neutral form has a positive formal charge. Any atom
with an octet and one bond less than its neutral form has a negative charge. For
example, oxygen is neutral with an octet and two bonds, such as in water. Therefore, anytime that oxygen has an octet and three bonds it will be positive, but with
an octet and only one bond it will be negative. We will see in the next section some
atoms that have an octet and two bonds more than their neutral form, and hence
have a plus two formal charge.

E. Exceptions to the Octet Rule
The Lewis model of covalent bonding focuses on valence electrons and the necessity
for each atom other than H participating in a covalent bond to have a completed
valence shell of eight electrons. Although most molecules formed by main-group
elements (Groups 1A–7A) have structures that satisfy the octet rule, there are
important exceptions to this rule.
One group of exceptions consists of molecules containing atoms of Group 3A
elements. The following graphic is a Lewis structure for BF3. In this uncharged
covalent compound, boron is surrounded by only six valence electrons. Aluminum
trichloride is an example of a compound in which aluminum, the element immediately below boron in Group 3A, has an incomplete valence shell. Because their
valence shells are only partially illed, trivalent compounds of boron and aluminum
exhibit a high reactivity with compounds that have extra electrons, enabling them

to ill their octets (Section 4.7).

F
F

6 electrons in the valence
shells of boron and aluminum

Cl
Cl

B
F

Boron trifluoride

Al
Cl

Aluminum trichloride

1.3 Functional Groups
Functional group
An atom or group of atoms within a
molecule that shows a characteristic
set of physical and chemical
properties.

Alcohol
A compound containing an !OH

(hydroxyl) group bonded to a
tetrahedral carbon atom.
Hydroxyl group
An !OH group.

16

Chapter 1

Carbon combines with other atoms (e.g., H, N, O, S, halogens) to form structural units called functional groups. Functional groups are important for three
reasons. First, they are the units by which we divide organic compounds into
classes. Second, they are sites of characteristic chemical reactions. A particular
functional group, in all compounds that contain it, undergoes the same types of
chemical reactions. Third, functional groups serve as a basis for naming organic
compounds.
We introduce here several of the functional groups we encounter early in this
course. At this point, our concern is only with pattern recognition. We shall have
more to say about the structure and properties of these functional groups in following chapters. A complete list of the major functional groups we study in this text is
presented on the inside front cover.

A. Alcohols
The functional group of an alcohol is an !OH (hydroxyl) group bonded to a tetrahedral carbon atom (a carbon having single bonds to four other atoms). Here is
the Lewis structure of ethanol.

Covalent Bonding and Shapes of Molecules

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Negatively charged carbon has three bonds and one lone pair, negatively charged
nitrogen has two bonds and two lone pairs, and negatively charged oxygen has one
bond and three lone pairs.
The guidelines for formal charge can be generalized. Any atom with an octet
plus one bond more than its neutral form has a positive formal charge. Any atom
with an octet and one bond less than its neutral form has a negative charge. For
example, oxygen is neutral with an octet and two bonds, such as in water. Therefore, anytime that oxygen has an octet and three bonds it will be positive, but with
an octet and only one bond it will be negative. We will see in the next section some
atoms that have an octet and two bonds more than their neutral form, and hence
have a plus two formal charge.

E. Exceptions to the Octet Rule
The Lewis model of covalent bonding focuses on valence electrons and the necessity
for each atom other than H participating in a covalent bond to have a completed
valence shell of eight electrons. Although most molecules formed by main-group
elements (Groups 1A–7A) have structures that satisfy the octet rule, there are
important exceptions to this rule.
One group of exceptions consists of molecules containing atoms of Group 3A
elements. The following graphic is a Lewis structure for BF3. In this uncharged
covalent compound, boron is surrounded by only six valence electrons. Aluminum
trichloride is an example of a compound in which aluminum, the element immediately below boron in Group 3A, has an incomplete valence shell. Because their
valence shells are only partially illed, trivalent compounds of boron and aluminum
exhibit a high reactivity with compounds that have extra electrons, enabling them
to ill their octets (Section 4.7).

F
F

6 electrons in the valence
shells of boron and aluminum

Cl
Cl

B
F

Boron trifluoride

Al
Cl

Aluminum trichloride

1.3 Functional Groups
Functional group
An atom or group of atoms within a
molecule that shows a characteristic
set of physical and chemical
properties.

Alcohol
A compound containing an !OH
(hydroxyl) group bonded to a
tetrahedral carbon atom.
Hydroxyl group
An !OH group.

16

Chapter 1

Carbon combines with other atoms (e.g., H, N, O, S, halogens) to form structural units called functional groups. Functional groups are important for three
reasons. First, they are the units by which we divide organic compounds into
classes. Second, they are sites of characteristic chemical reactions. A particular
functional group, in all compounds that contain it, undergoes the same types of
chemical reactions. Third, functional groups serve as a basis for naming organic
compounds.
We introduce here several of the functional groups we encounter early in this
course. At this point, our concern is only with pattern recognition. We shall have
more to say about the structure and properties of these functional groups in following chapters. A complete list of the major functional groups we study in this text is
presented on the inside front cover.

A. Alcohols
The functional group of an alcohol is an !OH (hydroxyl) group bonded to a tetrahedral carbon atom (a carbon having single bonds to four other atoms). Here is
the Lewis structure of ethanol.

Covalent Bonding and Shapes of Molecules

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.


E. Carboxylic Esters
A carboxylic ester, commonly referred to as an ester, is a derivative of a carboxylic acid
in which the hydrogen of the carboxyl group is replaced by a carbon-containing
group.

C

..

O

CH3

C

..

..

O

..

O

Carboxylic ester
A derivative of a carboxylic acid in
which H of the carboxyl group is
replaced by a carbon.

C

O

CH3

Methyl acetate

Functional
group

(an ester)

Example 1.12
The molecular formula of methyl acetate is C3H6O2. Draw the structural formula of
another ester with this same molecular formula.
Solution

There is only one other ester with this molecular formula. Its structural formula is

O
H

C

O

CH2

CH3

(we will usually write this HCOOC2H5)

Problem 1.12

Draw structural formulas for the four esters with the molecular formula C4H8O2.

F. Carboxylic Amides
A carboxylic amide, commonly referred to as an amide, is a derivative of a carboxylic
acid in which the !OH of the carboxyl group is replaced by an amine. As the
model shows, the group is planar, something we will explain later.
O
C

Carboxylic amide
A derivative of a carboxylic acid
in which the !OH is replaced by
an amine.

O
N

H 3C

C

N

CH3

CH3
Functional
group

Dimethylacetamide
(an amide)

1.4 Bond Angles and Shapes of Molecules
In Section 1.2, we used a shared pair of electrons as the fundamental unit of a
covalent bond and drew Lewis structures for several molecules and ions containing various combinations of single, double, and triple bonds. We can predict bond
angles in these and other molecules and ions in a very straightforward way using
a concept referred to as valence-shell electron-pair repulsion (VSEPR). VSEPR is
based on the electrons in an atom’s valence shell. These valence electrons may
be involved in the formation of single, double, or triple bonds, or they may be
1.4

VSEPR
A method for predicting bond angles
based on the idea that electron pairs
repel each other and keep as far
apart as possible.

Bond Angles and Shapes of Molecules

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

21


E. Carboxylic Esters
A carboxylic ester, commonly referred to as an ester, is a derivative of a carboxylic acid
in which the hydrogen of the carboxyl group is replaced by a carbon-containing
group.

C

..

O

CH3

C

..

..

O

..

O

Carboxylic ester
A derivative of a carboxylic acid in
which H of the carboxyl group is
replaced by a carbon.

C

O

CH3

Methyl acetate

Functional
group

(an ester)

Example 1.12
The molecular formula of methyl acetate is C3H6O2. Draw the structural formula of
another ester with this same molecular formula.
Solution

There is only one other ester with this molecular formula. Its structural formula is

O
H

C

O

CH2

CH3

(we will usually write this HCOOC2H5)

Problem 1.12

Draw structural formulas for the four esters with the molecular formula C4H8O2.

F. Carboxylic Amides
A carboxylic amide, commonly referred to as an amide, is a derivative of a carboxylic
acid in which the !OH of the carboxyl group is replaced by an amine. As the
model shows, the group is planar, something we will explain later.
O
C

Carboxylic amide
A derivative of a carboxylic acid
in which the !OH is replaced by
an amine.

O
N

H 3C

C

N

CH3

CH3
Functional
group

Dimethylacetamide
(an amide)

1.4 Bond Angles and Shapes of Molecules
In Section 1.2, we used a shared pair of electrons as the fundamental unit of a
covalent bond and drew Lewis structures for several molecules and ions containing various combinations of single, double, and triple bonds. We can predict bond
angles in these and other molecules and ions in a very straightforward way using
a concept referred to as valence-shell electron-pair repulsion (VSEPR). VSEPR is
based on the electrons in an atom’s valence shell. These valence electrons may
be involved in the formation of single, double, or triple bonds, or they may be
1.4

VSEPR
A method for predicting bond angles
based on the idea that electron pairs
repel each other and keep as far
apart as possible.

Bond Angles and Shapes of Molecules

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

21


E. Carboxylic Esters
A carboxylic ester, commonly referred to as an ester, is a derivative of a carboxylic acid
in which the hydrogen of the carboxyl group is replaced by a carbon-containing
group.

C

..

O

CH3

C

..

..

O

..

O

Carboxylic ester
A derivative of a carboxylic acid in
which H of the carboxyl group is
replaced by a carbon.

C

O

CH3

Methyl acetate

Functional
group

(an ester)

Example 1.12
The molecular formula of methyl acetate is C3H6O2. Draw the structural formula of
another ester with this same molecular formula.
Solution

There is only one other ester with this molecular formula. Its structural formula is

O
H

C

O

CH2

CH3

(we will usually write this HCOOC2H5)

Problem 1.12

Draw structural formulas for the four esters with the molecular formula C4H8O2.

F. Carboxylic Amides
A carboxylic amide, commonly referred to as an amide, is a derivative of a carboxylic
acid in which the !OH of the carboxyl group is replaced by an amine. As the
model shows, the group is planar, something we will explain later.
O
C

Carboxylic amide
A derivative of a carboxylic acid
in which the !OH is replaced by
an amine.

O
N

H 3C

C

N

CH3

CH3
Functional
group

Dimethylacetamide
(an amide)

1.4 Bond Angles and Shapes of Molecules
In Section 1.2, we used a shared pair of electrons as the fundamental unit of a
covalent bond and drew Lewis structures for several molecules and ions containing various combinations of single, double, and triple bonds. We can predict bond
angles in these and other molecules and ions in a very straightforward way using
a concept referred to as valence-shell electron-pair repulsion (VSEPR). VSEPR is
based on the electrons in an atom’s valence shell. These valence electrons may
be involved in the formation of single, double, or triple bonds, or they may be
1.4

VSEPR
A method for predicting bond angles
based on the idea that electron pairs
repel each other and keep as far
apart as possible.

Bond Angles and Shapes of Molecules

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

21


E. Carboxylic Esters
A carboxylic ester, commonly referred to as an ester, is a derivative of a carboxylic acid
in which the hydrogen of the carboxyl group is replaced by a carbon-containing
group.

C

..

O

CH3

C

..

..

O

..

O

Carboxylic ester
A derivative of a carboxylic acid in
which H of the carboxyl group is
replaced by a carbon.

C

O

CH3

Methyl acetate

Functional
group

(an ester)

Example 1.12
The molecular formula of methyl acetate is C3H6O2. Draw the structural formula of
another ester with this same molecular formula.
Solution

There is only one other ester with this molecular formula. Its structural formula is

O
H

C

O

CH2

CH3

(we will usually write this HCOOC2H5)

Problem 1.12

Draw structural formulas for the four esters with the molecular formula C4H8O2.

F. Carboxylic Amides
A carboxylic amide, commonly referred to as an amide, is a derivative of a carboxylic
acid in which the !OH of the carboxyl group is replaced by an amine. As the
model shows, the group is planar, something we will explain later.
O
C

Carboxylic amide
A derivative of a carboxylic acid
in which the !OH is replaced by
an amine.

O
N

H 3C

C

N

CH3

CH3
Functional
group

Dimethylacetamide
(an amide)

1.4 Bond Angles and Shapes of Molecules
In Section 1.2, we used a shared pair of electrons as the fundamental unit of a
covalent bond and drew Lewis structures for several molecules and ions containing various combinations of single, double, and triple bonds. We can predict bond
angles in these and other molecules and ions in a very straightforward way using
a concept referred to as valence-shell electron-pair repulsion (VSEPR). VSEPR is
based on the electrons in an atom’s valence shell. These valence electrons may
be involved in the formation of single, double, or triple bonds, or they may be
1.4

VSEPR
A method for predicting bond angles
based on the idea that electron pairs
repel each other and keep as far
apart as possible.

Bond Angles and Shapes of Molecules

Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

21