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72 Chemistry: Matter and Change
Solving Problems: A Chemistry Handbook
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER 8
Practice Problems
1. Draw the Lewis structure for each of the following molecules,
which contain only single covalent bonds. Refer to a periodic
table as necessary. Also state how many single covalent bonds
there are and how many lone pairs are on each bonded atom.
a. HCl
c. PH 3
b. SCl 2
d. SiF 4
Bond types and multiple bonds Single bonds are always sigma
bonds, bonds in which the electron pair is shared in an area centered
between the two atoms. Such bonds can form when the bonding
orbital is created by overlap of two s orbitals, an s and a p orbital, or
two p orbitals.
In some cases, atoms attain a noble gas configuration by sharing
more than one pair of electrons, forming a multiple covalent bond. In
a double covalent bond, two pairs of electrons are shared. In a triple
covalent bond, three pairs are shared. A multiple covalent bond
always consists of a sigma bond and at least one pi bond, a bond in
which parallel orbitals overlap. A pi bond occupies space above and
below the line that represents where the two atoms are joined.
Example Problem 8-2
Identifying Bond Types in a Molecule
The oxygen molecule has the formula O 2 . In this molecule, a total of
four electrons are shared by the two atoms. What type of bond is
this: single, double, or triple? Is the bond made up of sigma bonds,
pi bonds, or both?
The four shared electrons make up two bonding pairs, which means
that the bond is a double bond. In any multiple bond, there is one
sigma bond and the remaining bonds are pi bonds. Thus, in this
case, there are one sigma bond and one pi bond.
Practice Problems
2. Identify the bond types (single, double, or triple; and sigma or
pi) in each of the following diatomic molecules, given the number of shared electrons.
a. N 2 , six shared electrons
b. Br 2 , two shared electrons
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72 Chemistry: Matter and Change
Solving Problems: A Chemistry Handbook
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER 8
Practice Problems
1. Draw the Lewis structure for each of the following molecules,
which contain only single covalent bonds. Refer to a periodic
table as necessary. Also state how many single covalent bonds
there are and how many lone pairs are on each bonded atom.
a. HCl
c. PH 3
b. SCl 2
d. SiF 4
Bond types and multiple bonds Single bonds are always sigma
bonds, bonds in which the electron pair is shared in an area centered
between the two atoms. Such bonds can form when the bonding
orbital is created by overlap of two s orbitals, an s and a p orbital, or
two p orbitals.
In some cases, atoms attain a noble gas configuration by sharing
more than one pair of electrons, forming a multiple covalent bond. In
a double covalent bond, two pairs of electrons are shared. In a triple
covalent bond, three pairs are shared. A multiple covalent bond
always consists of a sigma bond and at least one pi bond, a bond in
which parallel orbitals overlap. A pi bond occupies space above and
below the line that represents where the two atoms are joined.
Example Problem 8-2
Identifying Bond Types in a Molecule
The oxygen molecule has the formula O 2 . In this molecule, a total of
four electrons are shared by the two atoms. What type of bond is
this: single, double, or triple? Is the bond made up of sigma bonds,
pi bonds, or both?
The four shared electrons make up two bonding pairs, which means
that the bond is a double bond. In any multiple bond, there is one
sigma bond and the remaining bonds are pi bonds. Thus, in this
case, there are one sigma bond and one pi bond.
Practice Problems
2. Identify the bond types (single, double, or triple; and sigma or
pi) in each of the following diatomic molecules, given the number of shared electrons.
a. N 2 , six shared electrons
b. Br 2 , two shared electrons
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