Chapter 5 Atoms and Bonding
Table of Contents
Chapter Preview
5.1 Atoms, Bonding, and the Periodic Table
5.2 Ionic Bonds
5.3 Covalent Bonds
5.4 Bonding in Metals
Chapter 5 Atoms and Bonding
Chapter Preview Questions
1. The atom is made of protons, electrons, and
a. valence electrons.
b. neutrons.
c. molecules.
d. ions.
Chapter 5 Atoms and Bonding
Chapter Preview Questions
1. The atom is made of protons, electrons, and
a. valence electrons.
b. neutrons.
c. molecules.
d. ions.
Chapter 5 Atoms and Bonding
Chapter Preview Questions
2. Reactant atoms and molecules interact to form
products with
a. identical physical properties.
b. different physical properties.
c. identical chemical properties.
d. different chemical properties.
Chapter 5 Atoms and Bonding
Chapter Preview Questions
2. Reactant atoms and molecules interact to form
products with
a. identical physical properties.
b. different physical properties.
c. identical chemical properties.
d. different chemical properties.
Chapter 5 Atoms and Bonding
Chapter Preview Questions
3. In chemical reactions, the number of atoms
a. varies according to the elements involved.
b. changes from one reactant to another.
c. stays the same.
d. depends on atom arrangement.
Chapter 5 Atoms and Bonding
Chapter Preview Questions
3. In chemical reactions, the number of atoms
a. varies according to the elements involved.
b. changes from one reactant to another.
c. stays the same.
d. depends on atom arrangement.
Chapter 5 Atoms and Bonding
Chapter Preview Questions
4. Compounds are formed by
a. combining two or more different elements.
b. bombarding atoms with high-speed particles.
c. combining two or more different nuclei.
d. dissolving a solid in a liquid.
Chapter 5 Atoms and Bonding
Chapter Preview Questions
4. Compounds are formed by
a. combining two or more different elements.
b. bombarding atoms with high-speed particles.
c. combining two or more different nuclei.
d. dissolving a solid in a liquid.
Chapter 5 Atoms and Bonding
Section 1: Atoms, Bonding, and the
Periodic Table
Standard 8.3.f: Students know how to use
the periodic table to identify elements in
simple compounds.
Chapter 5 Atoms and Bonding
Valence Electrons and Bonding
How is the reactivity of
elements related to valence
electrons in atoms?
Valence electrons
The number of valence
electrons in an atom of an
element determines the ways
in which the atom can bond
with other atoms.
• Electrons in the outermost
shell of an atom.
• Have the highest energy
level.
• Involved in bonding
between atoms.
Chapter 5 Atoms and Bonding
Valence Electrons and Bonding
Electron Dot Diagrams
Include the symbol for an
element surrounded by dots
that represent the number of
valence electrons.
Chapter 5 Atoms and Bonding
Valence Electrons and Bonding
Chemical Bond
The Rule of 8
•The force of attraction that holds
two atoms together as a result of
the rearrangement of electrons
between them.
•Electrons may be transferred from
one atom to another, or they may
be shared between the atoms.
Atoms are unlikely to react when
they have 8 valence electrons.
Chapter 5 Atoms and Bonding
How the Periodic Table Works
What does the periodic table
tell you about the atoms of
the elements?
The periodic table reveals the
underlying atomic structure of
atoms, including the
arrangement of the electrons.
Chapter 5 Atoms and Bonding
How the Periodic Table Works
The number of valence
electrons varies by group.
Group 3 through 12
elements do not follow the
same pattern as the other
groups!
•Group 1 elements have 1
valence electron.
•Group 2 elements have 2
valence electrons.
•Groups 3 – 12 have 1 to 2
valence electrons.
•Group 13 elements have 3
valence electrons.
•Groups 14 – 18 have 4, 5, 6,
7, and 8 valence electrons,
respectively.
Chapter 5 Atoms and Bonding
Example of Group 1 elements
Lithium Atom:
3 Protons/3 Neutrons
3 Electrons – 1 in Valence
Shell
Sodium Atom:
11 Protons/11 Neutrons
11 Electrons – 1 in Valence
Shell
Chapter 5 Atoms and Bonding
Section 1 Quick Quiz
The electrons involved in bonding between
atoms are
A.
B.
C.
D.
inside the nucleus.
closest to the nucleus.
positively charged.
valence electrons.
Answer:
D – Valence electrons
Chapter 5 Atoms and Bonding
Section 1 Quick Quiz
How many valence electrons do Group 13
elements have?
A.
B.
C.
D.
5
8
3
6
Answer:
C – 3 Valence Electrons
Chapter 5 Atoms and Bonding
Section 1 Quick Quiz
What is the greatest number of valence
electrons an atom can have?
A.
B.
C.
D.
5
8
3
6
Answer:
B – 8 Valence Electrons
Chapter 5 Atoms and Bonding
Section 1 Quick Quiz
Which Group of elements is the least reactive?
A.
B.
C.
D.
Group 1
Group 2
Group 17
Group 18
Answer:
D – Group 18
Chapter 5 Atoms and Bonding
Section 1 Quick Quiz
Each family in the periodic table has its own
characteristic properties based on the number
of
A.
B.
C.
D.
valence electrons
neutrons
protons
ions
Answer:
A – Valence electrons
Chapter 5 Atoms and Bonding
Section 1 Quick Quiz
If atoms of a halogen nonmetal (Group 17) gain
one electron, the atoms then have
A.
B.
C.
D.
no valence electrons.
7 valence electrons.
8 valence electrons.
17 valence electrons.
Answer:
C – 8 valence electrons
Chapter 5 Atoms and Bonding
Section 2: Ionic Bonds
Standard 8.3.b: Students know that compounds
are formed by combining two or more different
elements and that compounds have properties
that are different from their constituent elements.
Standard 8.3.c: Students know that atoms and
molecules form solids by building up repeating
patterns, such as the crystal structure of NaCl or
long-chain polymers.
Chapter 5 Atoms and Bonding
Ions
What is an ion?
How do ions form bonds?
•An ion is an atom or group of
atoms that has an electric
charge.
•When an atom loses an electron
it becomes a positive ion.
•When an atom gains an
electron it becomes a negative
ion.
Ionic bonds form as a result of
the attraction between positive
and negative ions.
Chapter 5 Atoms and Bonding
Ionic Compounds
Sodium has 1 valence
electron
Chlorine has 7 valence
electrons
http://web.jjay.cuny.edu/~acarpi/NSC/salt.htm
Chapter 5 Atoms and Bonding
Chemical Formulas and Names
How are the formulas and
names of ionic compounds
written?
Positive
Ion +
Negative
Ion -
NaCl
•When ionic compounds form,
the ions come together in a way
that balances out the charges
on the ions. The chemical
formula for the compound
reflects this balance.
•For an ionic compound, the
name of the positive ion comes
first, followed by the name of
the negative ion.
Chapter 5 Atoms and Bonding
Chemical Formulas and Names
What is a chemical
formula?
It is a combination of symbols
that shows the ratio of elements
in a compound.
What is a subscript?
A subscript tells you the ratio of
elements in the compound.
Chemical
Formula
CO2
Subscript
The ratio of Carbon to Oxygen
is 1 to 2.
Chapter 5 Atoms and Bonding
Properties of Ionic Compounds
What are the properties
of ionic compounds?
•In general, ionic compounds
are hard, brittle solids with high
melting points.
•When melted or dissolved in
water, they conduct electric
current.
Chapter 5 Atoms and Bonding
Section 2 Quick Quiz
When an atom loses an electron, it becomes a
A.
B.
C.
D.
positive ion.
negative ion.
neutral ion.
neutral atom.
Answer:
A – positive ion
Chapter 5 Atoms and Bonding
Section 2 Quick Quiz
An ionic bond is an attraction between
A.
B.
C.
D.
similarly charged ions.
oppositely charged ions.
neutral ions.
neutral atoms.
Answer:
B – oppositely charged ions
Chapter 5 Atoms and Bonding
Section 2 Quick Quiz
Ionic compounds are electrically
A.
B.
C.
D.
charged
positive
neutral
negative
Answer:
C – neutral
Chapter 5 Atoms and Bonding
Section 2 Quick Quiz
In what form can an ionic compound
conduct electricity?
A.
B.
C.
D.
as a solid
when dissolved in water
as a crystal
when warmed slightly
Answer:
B – when dissolved in water
Chapter 5 Atoms and Bonding
Section 2 Quick Quiz
Which of the following is a characteristic
property of ionic compounds?
A. They have low melting points.
B. They have low boiling points.
C. They form hard, brittle crystals with
characteristic shapes.
D. They contain no charged particles.
Answer:
C – They form hard, brittle crystals
with characteristic shapes
Chapter 5 Atoms and Bonding
Section 2 Quick Quiz
In the chemical formula for an ionic
compound, which item is written first?
A.
B.
C.
D.
positive ion
negative ion
subscript
charge
Answer:
A – positive ion
Chapter 5 Atoms and Bonding
Section 3: Covalent Bonds
Standard 8.3.b: Students know that compounds
are formed by combining two or more different
elements and that compounds have properties
that are different from their constituent elements.
Standard 8.7.c: Students know substances can
be classified by their properties, including their
melting temperature, density, hardness, and
thermal and electrical conductivity.
Chapter 5 Atoms and Bonding
How Covalent Bonds Form
What holds covalently
bonded atoms together?
The force that holds atoms
together in a covalent bond is the
attraction of each atom’s nucleus
for the shared pair of electrons.
Chapter 5 Atoms and Bonding
How Covalent Bonds Form
How do double and triple
bonds form?
Double and triple bonds can
form when atoms share more
than one pair of electrons.
Chapter 5 Atoms and Bonding
How Covalent Bonds Form
A carbon dioxide
molecule has two
double bonds.
Chapter 5 Atoms and Bonding
How Covalent Bonds Form
A nitrogen molecule is an
example of a triple bond
Chapter 5 Atoms and Bonding
Molecular Compounds
What are the properties
of molecular
compounds?
•Molecular compounds generally
have lower melting points and
boiling points than ionic
compounds.
•They do not conduct electric
current when melted or dissolved
in water.
Chapter 5 Atoms and Bonding
Unequal Sharing of Electrons
How does unequal
sharing of electrons
affect molecules?
Unequal sharing of electrons
causes the bonded atoms to
have slight electrical charges.
Polar bond
A covalent bond in which
electrons are shared unequally.
Nonpolar bond
A covalent bond in which
electrons are shared equally.
Chapter 5 Atoms and Bonding
Unequal Sharing of Electrons
Fluorine forms a
nonpolar bond with
another fluorine atom.
Chapter 5 Atoms and Bonding
Unequal Sharing of Electrons
In hydrogen fluoride,
fluorine attracts electrons
more strongly than
hydrogen does, so the bond
formed is polar.
Chapter 5 Atoms and Bonding
Unequal Sharing of Electrons
A carbon dioxide molecule
is a nonpolar molecule
because of its straight-line
shape.
Chapter 5 Atoms and Bonding
Unequal Sharing of Electrons
In contrast, a water molecule
is a polar molecule because
of its bent shape.
Chapter 5 Atoms and Bonding
Water Molecule – Polar Bonding
http://web.jjay.cuny.edu/~acarpi/NSC/salt.htm
Chapter 5 Atoms and Bonding
Section 3 Quick Quiz
A chemical bond formed when two atoms
share electrons is called a(n)
A.
B.
C.
D.
ionic bond
covalent bond
polyatomic bond
crystal bond
Answer:
B – covalent bond
Chapter 5 Atoms and Bonding
Section 3 Quick Quiz
What is a double bond?
A. a bond between two atoms
B. one pair of electrons shared between
two atoms
C. two pairs of electrons shared between
two atoms
D. two pairs of electrons shared between
four atoms
Answer:
C – two pairs of electrons shared
between two atoms
Chapter 5 Atoms and Bonding
Section 3 Quick Quiz
A covalent bond in which electrons are
shared unequally is
A.
B.
C.
D.
polar.
a double bond.
ionic.
polyatomic.
Answer:
A – polar
Chapter 5 Atoms and Bonding
Section 3 Quick Quiz
Water is polar and oil in nonpolar. What
happens when the two liquids are poured
into the same container?
A.
B.
C.
D.
Both liquids become nonpolar.
A gas is produced.
The liquids mix well.
The liquids do not mix.
Answer:
D – The liquids do not mix
Chapter 5 Atoms and Bonding
Section 4: Bonding in Metals
Standard 8.7.c: Students know substances can
be classified by their properties, including their
melting temperature, density, hardness, and
thermal and electrical conductivity.
Chapter 5 Atoms and Bonding
Metals and Alloys
How do the properties of
metals and alloys compare?
Alloys are generally stronger
and less reactive than the pure
metals from which they are
made.
Alloy
A mixture of two or more
elements, at least one of which
is a metal.
Example: Stainless steel – an
alloy of iron, carbon, nickel,
and chromium.
Chapter 5 Atoms and Bonding
Metallic Bonding
How do metal atoms
combine?
Metal atoms combine in
regular patterns in which the
valence electrons are free to
move from atom to atom.
What is a metallic
bond?
An attraction between a
positive metal ion and the
electrons around it
Chapter 5 Atoms and Bonding
Metallic Properties
How does metallic
bonding result in useful
properties of metals?
The “sea of electrons” model of
solid metals explains their ability
to conduct heat and electricity,
the ease with which they can be
made to change shape, and
their luster.
malleable
Able to be rolled into thin sheets
or beaten into complex shapes
ductile
Able to be bent easily and pulled
into thin strands or wires
Chapter 5 Atoms and Bonding
Section 4 Quick Quiz
A mixture that is made of two or more
elements-one that is a metal-that has the
properties of metal is a(n)
A.
B.
C.
D.
polymer
monomer
alloy
ceramic
Answer:
C – alloy
Chapter 5 Atoms and Bonding
Section 4 Quick Quiz
Steel is an alloy of one or more elements
combined with
A.
B.
C.
D.
copper
gold
iron
lead
Answer:
C – iron
Chapter 5 Atoms and Bonding
Section 4 Quick Quiz
Brass and steel are examples of
A.
B.
C.
D.
alloys
elements
pure metals
valence electrons
Answer:
A – alloys
Chapter 5 Atoms and Bonding
Section 4 Quick Quiz
Which of the following terms means that metals
can be rolled into thin sheets, as in aluminum
foil, or beaten into complex shapes?
A.
B.
C.
D.
polar
alloy
ductile
malleable
Answer:
D – malleable
Chapter 5 Atoms and Bonding
Section 4 Quick Quiz
Which of the following terms means that metals
can be pulled into thin strands or wires?
A.
B.
C.
D.
polar
alloy
ductile
malleable
Answer:
C – ductile