Question 1

Which statement does not describe a simple cubic unit cell?

Accepted Answer

A)  It results from square packing of atoms in layers. 
B)  The atoms lie at the corners of a cube. 
C)  Each atom has 6 nearest neighbors. 
D)  The stacking pattern can be represented by aaaa. 
E)  Each unit cell contains 8 atoms. 
A)  It results from square packing of atoms in layers. 
B)  The atoms lie at the corners of a cube. 
C)  Each atom has 6 nearest neighbors. 
D)  The stacking pattern can be represented by aaaa. 
E)  Each unit cell contains 8 atoms.

Question 2

Which of the following refers to an alloy in which the composition of the elements is constant?

Accepted Answer

A)  intermetallic 
B)  interstitial 
C)  stoichiometric 
D)  substitutional 
E)  homogeneous 
A)  intermetallic 
B)  interstitial 
C)  stoichiometric 
D)  substitutional 
E)  homogeneous

Question 3

If a face-centered cubic unit cell has a volume of 1.447 * 108 pm3 and the ions at the corners touch the ion on the face, what must be the ion's radius in picometers?

Accepted Answer

Question 4

Stainless steel is less susceptible to rusting than iron because ________

Accepted Answer

A)  it is coated with plastic. 
B)  the metals other than iron in the alloy form protective oxides. 
C)  the carbon within the alloy polymerizes to form a protective film. 
D)  the silicon within the alloy oxidizes to form a protective silicate layer. 
E)  the intermetallic compound formed is less reactive. 
A)  it is coated with plastic. 
B)  the metals other than iron in the alloy form protective oxides. 
C)  the carbon within the alloy polymerizes to form a protective film. 
D)  the silicon within the alloy oxidizes to form a protective silicate layer. 
E)  the intermetallic compound formed is less reactive.

Question 5

Aluminum (Al) crystallizes as a face-centered unit cell with an edge length of 404 pm. What is the atomic radius of aluminum?

Accepted Answer

A)  143 pm 
B)  202 pm 
C)  286 pm 
D)  175 pm 
E)  808 pm 
A)  143 pm 
B)  202 pm 
C)  286 pm 
D)  175 pm 
E)  808 pm

Question 6

A face-centered cubic unit cell contains ________ octahedral holes.

Accepted Answer

A)  1 
B)  4 
C)  8 
D)  12 
E)  13 
A)  1 
B)  4 
C)  8 
D)  12 
E)  13

Question 7

Gold (Au) has a face-centered cubic structure with a unit cell edge length of 407.8 pm. What is the calculated value of the density of gold based on this information?

Accepted Answer

A)  15.78 g/cm3 
B)  19.28 g/cm3 
C)  9.64 g/cm3 
D)  4.82 g/cm3 
E)  11.6 g/cm3 
A)  15.78 g/cm3 
B)  19.28 g/cm3 
C)  9.64 g/cm3 
D)  4.82 g/cm3 
E)  11.6 g/cm3

Question 8

Silver crystallizes with a face-centered cubic unit cell. The edge length is 407.7 pm. What is the volume of this unit cell?

Accepted Answer

A)  7.68 x 107 pm3 
B)  6.78 x 107 pm3 
C)  8.67 x 107 pm3 
D)  9.87 x 107 pm3 
E)  3.88 x 107 pm3 
A)  7.68 x 107 pm3 
B)  6.78 x 107 pm3 
C)  8.67 x 107 pm3 
D)  9.87 x 107 pm3 
E)  3.88 x 107 pm3

Question 9

Compare the packing efficiency of face-centered cubic aluminum and face-centered cubic lead.

Accepted Answer

A)  The efficiency of packing in the aluminum unit cell is higher because the aluminum atom is larger. 
B)  The efficiency of packing in the lead unit cell is higher because the lead atom is larger. 
C)  The efficiencies of packing in the unit cells of these two metals are the same. 
D)  The efficiency of packing in the aluminum unit cell is higher because the aluminum atom is smaller. 
E)  The efficiency of packing in the lead unit cell is higher because the lead atom is smaller. 
A)  The efficiency of packing in the aluminum unit cell is higher because the aluminum atom is larger. 
B)  The efficiency of packing in the lead unit cell is higher because the lead atom is larger. 
C)  The efficiencies of packing in the unit cells of these two metals are the same. 
D)  The efficiency of packing in the aluminum unit cell is higher because the aluminum atom is smaller. 
E)  The efficiency of packing in the lead unit cell is higher because the lead atom is smaller.

Question 10

Band theory of bonding in solids ________

Accepted Answer

A)  is an extension of molecular orbital theory. 
B)  describes bonds as rubber bands. 
C)  does not apply to any type of solid other than metals. 
D)  explains bond formation in metals, but not their physical properties. 
E)  All of the above are correct. 
A)  is an extension of molecular orbital theory. 
B)  describes bonds as rubber bands. 
C)  does not apply to any type of solid other than metals. 
D)  explains bond formation in metals, but not their physical properties. 
E)  All of the above are correct.

Question 11

Ceramic insulators ________

Accepted Answer

A)  do not have a band structure. 
B)  have a band structure, but no electrons are in these bands. 
C)  have two half-filled bands, neither of which is capable of conducting electricity. 
D)  have a full band that is well separated in energy from an empty band. 
E)  do not exist; all ceramics are good thermal and electrical conductors. 
A)  do not have a band structure. 
B)  have a band structure, but no electrons are in these bands. 
C)  have two half-filled bands, neither of which is capable of conducting electricity. 
D)  have a full band that is well separated in energy from an empty band. 
E)  do not exist; all ceramics are good thermal and electrical conductors.

Question 12

Aluminum is resistant to corrosion because of ________

Accepted Answer

A)  its positive oxidation potential. 
B)  its low density. 
C)  the formation of a protective surface film of aluminum oxide. 
D)  the formation of a protective surface film of aluminum nitride. 
E)  its lack of reactivity toward oxygen. 
A)  its positive oxidation potential. 
B)  its low density. 
C)  the formation of a protective surface film of aluminum oxide. 
D)  the formation of a protective surface film of aluminum nitride. 
E)  its lack of reactivity toward oxygen.

Question 13

For an alloy composed of two elements whose composition can be variable, if the radii of the two elements are approximately the same, the alloy is most likely to be a(n) ________ alloy, while if the radii are significantly different, the alloy is most likely to be a(n) ________ alloy.

Accepted Answer

substituti

Question 14

The alpha form of polonium (Po) has a density of 9.196 g/cm3 and crystallizes in a simple cubic structure. What is the atomic radius of polonium in picometers?

Accepted Answer

Question 15

As an analog of graphite, a material composed of boron and nitrogen (B-N) has been prepared. Why do these elements make a good substitute for the element in graphite?
I.They are all elements with electrons in the 2p subshell.
II.The sum of the valence electrons of one boron atom and one nitrogen atom is the same as the number of valence electrons on two carbon atoms.
III.Boron and nitrogen have suitable 2p orbital overlap.

Accepted Answer

A)  I only 
B)  II only 
C)  III only 
D)  I and II only 
E)  I, II, and III 
A)  I only 
B)  II only 
C)  III only 
D)  I and II only 
E)  I, II, and III

Question 16

GaAs and AlGaAs2 are examples of ________ semiconductors.

Accepted Answer

A)  light-emitting diode (LE
D)  
B)  sound-emitting 
C)  np 
D)  non- 
E)  dual voltage 
A)  light-emitting diode (LE
D)  
B)  sound-emitting 
C)  np 
D)  non- 
E)  dual voltage

Question 17

According to band theory, when the lower energy ________ band overlaps with the higher energy ________ band, the material will act as a ________ of electricity.

Accepted Answer

valence; c

Question 18

When silicon is doped with gallium, electrical conduction increases because ________

Accepted Answer

A)  gallium has fewer valence electrons than silicon, so holes are created in the valence band of silicon. 
B)  gallium has more valence electrons than silicon, so electrons are added to the conduction band of silicon. 
C)  gallium causes electrons to be transferred from the valence band of silicon to the conduction band of silicon. 
D)  gallium causes electrons to be transferred from the conduction band of silicon to the valence band of silicon. 
E)  gallium is a better conductor of electricity than silicon. 
A)  gallium has fewer valence electrons than silicon, so holes are created in the valence band of silicon. 
B)  gallium has more valence electrons than silicon, so electrons are added to the conduction band of silicon. 
C)  gallium causes electrons to be transferred from the valence band of silicon to the conduction band of silicon. 
D)  gallium causes electrons to be transferred from the conduction band of silicon to the valence band of silicon. 
E)  gallium is a better conductor of electricity than silicon.

Question 19

Identify the solid that has a high melting point, is hard and brittle, and conduct electricity when liquefied.

Accepted Answer

A)  a molecular solid 
B)  a metal 
C)  a covalent network 
D)  an ionic solid 
E)  an amorphous solid 
A)  a molecular solid 
B)  a metal 
C)  a covalent network 
D)  an ionic solid 
E)  an amorphous solid

Question 20

Aluminum alloys are more desirable than steel in some applications because of their relatively ________

Accepted Answer

A)  low density. 
B)  low cost. 
C)  high luster. 
D)  high warmth to touch. 
E)  high conductivity. 
A)  low density. 
B)  low cost. 
C)  high luster. 
D)  high warmth to touch. 
E)  high conductivity.

Exam 12: Solids: Structures and Applications

Which statement does not describe a simple cubic unit cell?

Which of the following refers to an alloy in which the composition of the elements is constant?

If a face-centered cubic unit cell has a volume of 1.447 * 108 pm3 and the ions at the corners touch the ion on the face, what must be the ion's radius in picometers?

Stainless steel is less susceptible to rusting than iron because ________

Aluminum (Al) crystallizes as a face-centered unit cell with an edge length of 404 pm. What is the atomic radius of aluminum?

A face-centered cubic unit cell contains ________ octahedral holes.

Gold (Au) has a face-centered cubic structure with a unit cell edge length of 407.8 pm. What is the calculated value of the density of gold based on this information?

Silver crystallizes with a face-centered cubic unit cell. The edge length is 407.7 pm. What is the volume of this unit cell?

Compare the packing efficiency of face-centered cubic aluminum and face-centered cubic lead.

Band theory of bonding in solids ________

Ceramic insulators ________

Aluminum is resistant to corrosion because of ________

For an alloy composed of two elements whose composition can be variable, if the radii of the two elements are approximately the same, the alloy is most likely to be a(n) ________ alloy, while if the radii are significantly different, the alloy is most likely to be a(n) ________ alloy.

The alpha form of polonium (Po) has a density of 9.196 g/cm3 and crystallizes in a simple cubic structure. What is the atomic radius of polonium in picometers?

GaAs and AlGaAs2 are examples of ________ semiconductors.

According to band theory, when the lower energy ________ band overlaps with the higher energy ________ band, the material will act as a ________ of electricity.

When silicon is doped with gallium, electrical conduction increases because ________

Identify the solid that has a high melting point, is hard and brittle, and conduct electricity when liquefied.

Aluminum alloys are more desirable than steel in some applications because of their relatively ________

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Stoichiometry: Mass, Formulas, and Reactions

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: the Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Organic Chemistry: Fuels, Pharmaceuticals, Materials, and Life

Chemical Kinetics: Reactions in the Air We Breathe

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acid-Base and Solubility Equilibria: Reactions in Soil and Water

Metal Ions: Colorful and Essential

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Electrochemistry: the Quest for Clean Energy

Biochemistry: the Compounds of Life

Nuclear Chemistry: Applications to Energy and Medicine

Life and the Periodic Table

Filters

If a face-centered cubic unit cell has a volume of 1.447 * 10⁸ pm³ and the ions at the corners touch the ion on the face, what must be the ion's radius in picometers?

For an alloy composed of two elements whose composition can be variable, if the radii of the two elements are approximately the same, the alloy is most likely to be a(n) alloy, while if the radii are significantly different, the alloy is most likely to be a(n) alloy.

The alpha form of polonium (Po) has a density of 9.196 g/cm³ and crystallizes in a simple cubic structure. What is the atomic radius of polonium in picometers?

GaAs and AlGaAs₂ are examples of ________ semiconductors.

According to band theory, when the lower energy band overlaps with the higher energy band, the material will act as a of electricity.