7.3 Review

Which of the following best describes the valence electrons of metal atoms?

• They are tightly bound to the nucleus.

• They are shared equally between atoms.

• They are free to move throughout the metal lattice.

• They are involved in covalent bonding.

What is the importance of alloys and how do the two main types compare and contrast?

• Alloys enhance material properties and are classified into substitutional and interstitial types, which differ in atomic arrangement.

• Alloys are used to reduce costs and are classified into metallic and non-metallic types, which differ in conductivity.

• Alloys are primarily used for aesthetic purposes and are classified into ferrous and non-ferrous types, which differ in color.

• Alloys are used to increase weight and are classified into organic and inorganic types, which differ in composition.

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Metallic bonds are characterized by:

• The sharing of electron pairs between atoms

• The transfer of electrons from one atom to another

• The attraction between free-floating valence electrons and positively charged metal ions

• The sharing of electrons between non-metal atoms

Which of the following is a property of metals?

• Poor conductor of electricity

• Brittle

• Good conductor of heat and electricity

• Non-ductile

Why are metals considered durable compared to ionic compounds?

• Metals have a sea of electrons that allows them to be malleable and ductile.

• Metals form strong ionic bonds that make them hard and brittle.

• Metals have weak intermolecular forces that make them flexible.

• Metals have a rigid lattice structure that makes them durable.

Fill in the blank: An ounce of gold can be drawn into a wire more than ____ miles long.

• 40

• 20

• 60

• 80

Match the following elements with their properties:

• Uranium

• I'm so shiny!

• Oxygen

• I am a very good conductor.

• Copper

• I help produce clean energy.

• Gold

• I help sustain life.

Why are alloys important?

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Fill in the blank: Compared to pure metals, alloys have better ________ resistance, are less brittle, and have a higher strength and better workability.

• corrosion

• heat

• electrical

• magnetic

Which of the following is an example of an alloy?

• Pure silver

• Brass

• Copper

• Zinc