Transcript chapter07_section03_edit a

Chemistry
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7.3
Bonding in Metals
You have probably seen
decorative fences,
railings, or weathervanes
made of a metal called
wrought iron. In this
section, you will learn
how metallic properties
derive from the way that
metal ions form bonds
with one another.
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7.3
Bonding in Metals > Metallic Bonds and Metallic Properties
Metallic Bonds and Metallic Properties
How can you model the valence
electrons of metal atoms?
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7.3
Bonding in Metals > Metallic Bonds and Metallic Properties
The valence electrons of metal atoms
can be modeled as a sea of electrons.
The valence electrons are mobile and can
drift freely from one part of the metal to
another.
Metallic bonds consist of the attraction of
the free-floating valence electrons for the
positively charged metal ions.
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7.3
Bonding in Metals > Metallic Bonds and Metallic Properties
Metals are ductile—that
is, they can be drawn into
wires.
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7.3
Bonding in Metals > Metallic Bonds and Metallic Properties
A force can change the shape of a metal. A force
can shatter an ionic crystal.
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7.3
Bonding in Metals > Crystalline Structure of Metals
Crystalline Structure of Metals
How are metal atoms arranged?
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Bonding in Metals > Crystalline Structure of Metals
These tomatoes have
a closed-packed
arrangement. Similar
arrangements can be
found in the crystalline
structure of metals.
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7.3
Bonding in Metals > Crystalline Structure of Metals
Metal atoms are arranged in very compact
and orderly patterns.
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7.3
Bonding in Metals > Alloys
Alloys
Why are alloys important?
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Bonding in Metals > Alloys
Alloys are mixtures composed of two or more
elements, at least one of which is a metal.
Alloys are important because their
properties are often superior to those
of their component elements.
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Bonding in Metals > Alloys
Bicycle frames are often made of titanium alloys
that contain aluminum and vanadium.
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7.3
Bonding in Metals > Alloys
The most important alloys
today are steels. Steels
have a wide range of useful
properties, such as
corrosion resistance,
ductility, hardness, and
toughness.
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7.3 Section Quiz.
1. The valence electrons of metals can be
modeled as
a.
a body-centered cube.
b.
octets of electrons.
c.
a rigid array of electrons.
d.
a sea of electrons.
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7.3 Section Quiz.
2. In most metals, the atoms are
a. free to move from one part of the metal to
another.
b. arranged in a compact and orderly pattern.
c. placed at irregular locations.
d. randomly distributed.
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7.3 Section Quiz.
3. Alloys are important because they
a.
are pure substances.
b. are the ores from which metals can be
refined.
c. can have properties superior to those of
their components.
d. are produced by the combustion of metals.
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Bonding in Metals > Concept Map 7
Concept Map 7 Solve the Concept Map with
the help of an interactive guided tutorial.
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END OF SHOW