How do metals bond?
Utah OER DOE
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Printed: February 28, 2016
AUTHOR
Utah OER DOE
www.ck12.org
C HAPTER
Chapter 1. How do metals bond?
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How do metals bond?
Objectives
• Describe how metallic bonds are formed.
• List the properties of metallic compounds.
FIGURE 1.1
The thick, rigid trunk of the oak tree
on the left might crack and break in a
strong wind. The slim, flexible trunk of
the willow tree on the right might bend
without breaking. In one way, metals are
like willow trees. They can bend without
breaking.
That’s because metals form
special bonds called metallic bonds.
What Are Metallic Bonds?
FIGURE 1.2
Metallic bonds.
Metallic bonds (a bond between metal atoms in which the valence electrons are free flowing) are present in
aluminum foil, gold jewelry, and the steel in a car. The valence electrons of metals move freely in this way because
metals have relatively low electronegativity, or attraction to electrons. The positive metal ions form a lattice-like
structure held together by all the metallic bonds.
Q: Why do metallic bonds form only in elements that are metals? Why don’t similar bonds form in elements that
are nonmetals?
A: Metal atoms readily give up valence electrons and become positive ions whenever they form bonds. When
nonmetals bond together, the atoms share valence electrons and do not become ions. For example, when oxygen
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atoms bond together they form oxygen molecules in which two oxygen atoms share two pairs of valence electrons
equally, so neither atom becomes charged.
Metallic Bonds and the Properties of Metals
The valence electrons surrounding metal ions are constantly moving. This makes metals good conductors of
electricity. The lattice-like structure of metal ions is strong but quite flexible. This allows metals to bend without
breaking. Metals are both ductile (can be shaped into wires) and malleable (can be shaped into thin sheets).
You can learn more about metallic bonds and the properties of metals at this URL:
• http://bit.ly/1a8xCnv
MEDIA
Click image to the left or use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/177533
Q: Look at the metalworker in the Figure below. He’s hammering a piece of hot iron in order to shape it. Why
doesn’t the iron crack when he hits it?
A: The iron ions can move within the “sea” of electrons around them. They can shift a little closer together or farther
apart without breaking the metallic bonds between them. Therefore, the metal can bend rather than crack when the
hammer hits it.
FIGURE 1.3
Metal worker shaping iron metal.
Summary
• Metallic bonds are the force of attraction between positive metal ions and the valence electrons that are
constantly moving around them. The ions form a lattice-like structure held together by the metallic bonds.
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Chapter 1. How do metals bond?
• Metallic bonds explain why metals can conduct electricity and bend without breaking.
Think like a Chemist
Watch the video about metallic bonds at the following URL, and then answer the questions below.
• http://bit.ly/1a8xCnv
MEDIA
Click image to the left or use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/177533
1.
2.
3.
4.
5.
6.
What is electricity? Why can metals conduct electricity?
What can metals conduct besides electricity?
How could you use an empty pop can to demonstrate that metals can bend without breaking?
What are metallic bonds?
How do metallic bonds relate to the properties of metals?
The iron in the metalworking picture above is red hot. Infer why the metalworker heats the iron when he
shapes it.
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