Covalent Bond Lesson

The Covalent Bond

Lesson 1

Focus Question

How do atoms bond in covalent
molecules?

New Vocabulary

covalent bond
molecule
Lewis structure
sigma bond
pi bond
endothermic
exothermic

Review Vocabulary

chemical bond: the force that holds two atoms
together

Why do atoms bond?

Gaining Stability
•

The stability of an atom, ion, or compound is
related to its energy: lower energy states are
more stable.

•

Ionic bonds, metals, and nonmetals gain stability
by transferring (gaining or losing) electrons to
form ions with stable noble-gas electron
configurations.

•

Valence electron sharing allows atoms to acquire
the stable electron configuration of noble gases.

Multiple Choice

What elements generally make an ionic bond?

• metal and nonmetal

• 2 or more nonmetals

• metal

• none of the above

Multiple Choice

The outermost electrons of an atom are __________.

• outermost electron

• Lewis electrons

• valence electrons

• octet electrons

Multiple Choice

How many valence electrons should an element have for it to be considered as a STABLE element?

• 2

• 10

• 6

• 8

What is a covalent bond?

Shared Electrons
• Atoms in non-ionic compounds share

electrons.

• A covalent bond is a chemical bond that

results from electron sharing.

• A molecule is formed when two or more

atoms bond covalently.

• The majority of covalent bonds form between

atoms of nonmetallic elements.

What is a covalent bond?

Covalent Bond Formation
• Diatomic molecules (H2, N2, F2, O2, I2, Cl2, Br2)

exist because the two-atom molecules are
more stable than the individual atoms.

What is a covalent bond?

• The most stable arrangement of atoms exists

at the point of maximum net attraction,
where the atoms bond covalently and form a
molecule.

Multiple Choice

Name the type of bonding in which the electrons are shared.

• Ionic bonding

• Covalent bonding

• Metallic bonding

Multiple Choice

What are diatomic elements?

• Elements that form two-atom molecules when not combined in a compound.

• Two elements that combine with one atom from each element.

• Elements that are always in pairs no matter what.

Multiple Choice

Is Fe₂ a diatomic element?

• Yes

• No

Multiple Choice

Is O₂ a diatomic element?

• Yes

• No

Multiple Choice

The covalent bond forms between

• a metal and nonmetal

• a nonmetal and nonmetal

• a metal and metal

Single Covalent Bonds

•

When only one pair of electrons is shared, the
result is a single covalent bond.

•

The figure shows two hydrogen atoms forming a
hydrogen molecule with a single covalent bond,
resulting in an electron configuration like helium.

•

In a Lewis structure,dots or a line are used to
symbolize a single covalent bond.

TYPES OF COVALENT BONDS

• SINGLE Covalent Bonds

• DOUBLE Covalent Bonds

• TRIPLE Covalent Bonds

Single Covalent Bonds

Group 17 and Single Bonds
•

The halogens—the group 17 elements—have 7
valence electrons and form single covalent bonds
with atoms of other non-metals.

Group 16 and Single Bonds
•

Atoms in group 16 can share two electrons and
form two covalent bonds.

•

Water is formed from one oxygen with two
hydrogen atoms covalently bonded to it.

Single Covalent Bonds

Group 15 and Single Bonds
•

Atoms in group 15 form three single covalent
bonds, such as in ammonia.

Group 14 and Single Bonds
•

Atoms of group 14 elements form four single
covalent bonds, such as in methane.

Single Covalent Bonds

The Sigma Bond
•

Single covalent bonds are called sigma bonds.

•

They occur when the pair of shared electrons is in
an area centered between the two atoms.

Multiple Choice

How are covalent bonds explained?

• When one atom takes the other atom's electron

• When the atom shares an electron with an another atom

• When the two nucleus merge

• When the neutrons leave the nucleus

Multiple Choice

How many are shared in a single bond?

• 2 pairs

• 4

• 2

• 1

Multiple Choice

Which of these is not a real bond in chemistry?

• James

• Ionic

• Covalent

Multiple Choice

How many sigma bonds does this have? 

• 1

• 2

• 3

• 4

Multiple Choice

How many sigma bonds are in the following molecule?

• 0

• 4

• 8

• 12

• 16

Multiple Covalent Bonds

Double Bonds
•

A double bond forms when two pairs of electrons are shared
between two atoms.

•

In a. of the figure below, two oxygen molecules form a
double bond.

Multiple Covalent Bonds

Triple Bonds
•

A triple bond forms when three pairs of electrons are shared
between two atoms.

•

In b. of the figure below, a triple bond forms between
two nitrogen atoms.

Multiple Covalent Bonds

The pi Bond
•

A multiple covalent bond
consists of one sigma bond
and at least one pi bond.
The figure shows the
multiple bond between
carbon atoms in C2H4.

•

A pi bond forms when
parallel orbitals overlap
and share electrons.

Multiple Choice

How many pi bonds does this have? 

• 1

• 2

• 3

• 4

Multiple Choice

How many sigma bonds does this have? 

• 1

• 2

• 3

• 4

Multiple Choice

How many sigma and pi bonds does this have?

• 1 sigma and 1 pi

• 2 sigma and 1 pi

• 1 sigma and 2 pi

• 2 sigma and 2 pi

Multiple Choice

How many pi bonds are there in a double bond? 

• 0

• 1

• 2

• 3

Multiple Choice

How many sigma bonds are there in a triple bond? 

• 0

• 1

• 2

• 3

Multiple Choice

How many sigma bonds are in the following molecule?

• 0

• 1

• 2

• 5

• 6

The Strength of Covalent Bonds

Bond Length
•

The strength depends on the distance between the two nuclei, or
bond length.

•

As length increases, strength decreases.

Bonds and Energy
•

The amount of energy required to break a bond is called the bond
dissociation energy.

•

The shorter the bond length, the greater the energy required to
break it.

The Strength of Covalent Bonds

• An endothermic reactionoccurs when a greater

amount of energy is required to break the existing
bonds in the reactants than is released when the new
bonds form in the products.

• An exothermic reactionoccurs when more energy is

released during product bond formation than is
required to break bonds in the reactants.

Multiple Choice

what type of bond is the strongest

• single
• Double
• coordination
• triple

Multiple Choice

How many electrons are shared in a triple bond?

• 6

• 3

• 6 pairs

• 5

Think of the quiz answers before moving

to the next slide

Quiz

Atoms in nonionic pairs gain or lose electrons.

D

Atoms with lower energy states are more stable.

C

Atoms with higher energy states are more stable.

B

Metals gain stability by sharing electrons to form ions.

A

Which of the following is true?

1.

Quiz

Atoms in nonionic pairs gain or lose electrons.

D

Atoms with lower energy states are more stable.

C

Atoms with higher energy states are more stable.

B

Metals gain stability by sharing electrons to form ions.

A

Which of the following is true?

1.

CORRECT

Quiz

molecule

D

covalent bond

C

metallic bond

B

ionic bond

A

Which term refers to a chemical bond that
results from sharing valence electrons?

2.

Quiz

molecule

D

covalent bond

C

metallic bond

B

ionic bond

A

Which term refers to a chemical bond that
results from sharing valence electrons?

2.

CORRECT

8

D

3

C

1

A

2

B

How many electrons do group 17 elements need to form
an octet?

3.

Quiz

8

D

3

C

1

A

2

B

How many electrons do group 17 elements need to form
an octet?

3.

CORRECT

Quiz

Quiz

sigma

D

Lewis

C

ionic

B

pi

A

Which term refers to single covalent bonds?

4.

Quiz

sigma

D

Lewis

C

ionic

B

pi

A

Which term refers to single covalent bonds?

4.

CORRECT

None of the above is true.

D

It consists of two sigma bonds and more than two pi
bonds.

C

It consists of one sigma bond and at least one
pi bond.

A

It consists of more than one sigma bond.

B

Which of the following is true of a multiple covalent
bond?

5.

Quiz

None of the above is true.

D

It consists of two sigma bonds and more than two pi
bonds.

C

It consists of one sigma bond and at least one
pi bond.

A

It consists of more than one sigma bond.

B

Which of the following is true of a multiple covalent
bond?

5.

CORRECT

Quiz