Question 1

Compare the packing efficiency of face-centered cubic gold and face-centered cubic sodium chloride considering all the atoms.

Accepted Answer

A) The efficiency of packing in the gold unit cell is higher. 
B) The efficiency of packing in the sodium chloride unit cell is higher. 
C) The efficiencies of packing in the two lattices are the same. 
D) Packing efficiencies cannot be defined for one or both of these. 
E) There is no way to compare without further information. 
A) The efficiency of packing in the gold unit cell is higher. 
B) The efficiency of packing in the sodium chloride unit cell is higher. 
C) The efficiencies of packing in the two lattices are the same. 
D) Packing efficiencies cannot be defined for one or both of these. 
E) There is no way to compare without further information.

Question 2

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 3

In the sodium chloride unit cell, the chloride ions form a cube in which each side is arranged like the following figure. The circles represent the positions of the chloride ions on one square face of the cube. All the other faces are the same. What is the name of this unit cell?

Accepted Answer

A) simple cubic 
B) chloride-centered cubic 
C) face-centered cubic 
D) x-face cubic 
E) body-centered cubic 
A) simple cubic 
B) chloride-centered cubic 
C) face-centered cubic 
D) x-face cubic 
E) body-centered cubic

Question 4

In interstitial alloys, a maximum ( F1F1F1S1F1F1F10 1) atomic radius ratio would indicate an atom would likely fit in what type of hole(s)?

Accepted Answer

A) tetrahedral hole 
B) octahedral hole 
C) cubic hole 
D) both an octahedral and tetrahedral hole 
E) both an octahedral and cubic hole 
A) tetrahedral hole 
B) octahedral hole 
C) cubic hole 
D) both an octahedral and tetrahedral hole 
E) both an octahedral and cubic hole

Question 5

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

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Question 6

The alpha form of polonium (Po) crystallizes as a simple cubic unit cell with an edge length of 335 pm. What is the atomic radius of polonium?

Accepted Answer

A) 84 pm 
B) 168 pm 
C) 335 pm 
D) 175 pm 
E) 808 pm 
A) 84 pm 
B) 168 pm 
C) 335 pm 
D) 175 pm 
E) 808 pm

Question 7

Which of the following unit cells has the highest packing efficiency?

Accepted Answer

A) simple cubic 
B) face-centered cubic 
C) body-centered cubic 
D) both face-centered and body-centered cubic 
E) Simple, face-centered, and body-centered cubic all have the same packing efficiency. 
A) simple cubic 
B) face-centered cubic 
C) body-centered cubic 
D) both face-centered and body-centered cubic 
E) Simple, face-centered, and body-centered cubic all have the same packing efficiency.

Question 8

A cubic closest-packed structure has hexagonally arranged layers of atoms stacking in the series ________

Accepted Answer

A) ababab 
B) abcabcabc. 
C) abcbabcbabcba. 
D) abacabacaba. 
E) aaaaaa. 
A) ababab 
B) abcabcabc. 
C) abcbabcbabcba. 
D) abacabacaba. 
E) aaaaaa.

Question 9

What type of hole is depicted below? The gray circle represents the top layer.

Accepted Answer

A) tetrahedral hole 
B) octahedral hole 
C) cubic hole 
D) both an octahedral and tetrahedral hole 
E) both an octahedral and cubic hole 
A) tetrahedral hole 
B) octahedral hole 
C) cubic hole 
D) both an octahedral and tetrahedral hole 
E) both an octahedral and cubic hole

Question 10

A rock salt structure has smaller ions in ________

Accepted Answer

A) cubic holes. 
B) tetrahedral holes. 
C) hexagonal holes. 
D) octahedral holes. 
E) the usual atomic positions in the unit cell, i.e., not in holes. 
A) cubic holes. 
B) tetrahedral holes. 
C) hexagonal holes. 
D) octahedral holes. 
E) the usual atomic positions in the unit cell, i.e., not in holes.

Question 11

Draw a few subunits of the polymer derived from the following molecule.

Accepted Answer

The answer of Draw a few subunits of the polymer...

Question 12

Iron (Fe) crystallizes as a body-centered unit cell with an edge length of 287 pm. What is the atomic radius of iron in picometers?

Accepted Answer

The answer of Iron (Fe) crystallizes as a body-centered unit...

Question 13

At a historic Civil War battleground, a stack of cannonballs looked like the picture below on the far left. Removing the top cannonball resulted in the middle view, and removing the next layer resulted in the view on the right. What sort of packing was used in stacking the cannonballs?

Accepted Answer

A) cannonball closest-packed 
B) hexagonal closest-packed 
C) cubic closest-packed 
D) random-packed 
E) body-centered closest-packed 
A) cannonball closest-packed 
B) hexagonal closest-packed 
C) cubic closest-packed 
D) random-packed 
E) body-centered closest-packed

Question 14

Gold has a face-centered cubic structure with a unit cell edge length of 407.8 pm. What is the contribution to the density from each individual gold atom?

Accepted Answer

A) 21.44 g/cm3 
B) 26.20 g/cm3 
C) 13.1 g/cm3 
D) 6.55 g/cm3 
E) 19.28 g/cm3 
A) 21.44 g/cm3 
B) 26.20 g/cm3 
C) 13.1 g/cm3 
D) 6.55 g/cm3 
E) 19.28 g/cm3

Question 15

What type of hole is depicted below? The gray circles represent the top layer.

Accepted Answer

A) tetrahedral hole 
B) octahedral hole 
C) cubic hole 
D) both an octahedral and tetrahedral hole 
E) both an octahedral and cubic hole 
A) tetrahedral hole 
B) octahedral hole 
C) cubic hole 
D) both an octahedral and tetrahedral hole 
E) both an octahedral and cubic hole

Question 16

An atom in a particular unit cell has 6 nearest neighbor atoms around it. Which unit cell(s) are possible?

Accepted Answer

A) simple cubic 
B) body-centered cubic 
C) face-centered cubic 
D) hexagonal 
E) face-centered cubic or hexagonal 
A) simple cubic 
B) body-centered cubic 
C) face-centered cubic 
D) hexagonal 
E) face-centered cubic or hexagonal

Question 17

Compare the packing efficiency of face-centered cubic copper and simple cubic polonium.

Accepted Answer

A) The efficiency of packing in the copper unit cell is higher. 
B) The efficiency of packing in the polonium unit cell is higher. 
C) The efficiencies of packing in the two lattices are the same. 
D) Packing efficiencies cannot be defined for one or both of these. 
E) There is no way to compare without further information. 
A) The efficiency of packing in the copper unit cell is higher. 
B) The efficiency of packing in the polonium unit cell is higher. 
C) The efficiencies of packing in the two lattices are the same. 
D) Packing efficiencies cannot be defined for one or both of these. 
E) There is no way to compare without further information.

Question 18

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

Accepted Answer

The answer of Aluminum (Al) crystallizes as a face-centered unit...

Question 19

The face-centered cubic unit cell has ________ tetrahedral holes.

Accepted Answer

A) 0 
B) 1 
C) 4 
D) 8 
E) 12 
A) 0 
B) 1 
C) 4 
D) 8 
E) 12

Question 20

Sphalerite (ZnS) is the chief ore of zinc. In the unit cell of sphalerite, ________

Accepted Answer

A) all of the octahedral holes are filled with cations. 
B) half of the octahedral holes are filled with cations. 
C) all of the tetrahedral holes are filled with cations. 
D) half of the tetrahedral holes are filled with cations. 
E) cations occupy standard atomic positions in the unit cell, not the holes. 
A) all of the octahedral holes are filled with cations. 
B) half of the octahedral holes are filled with cations. 
C) all of the tetrahedral holes are filled with cations. 
D) half of the tetrahedral holes are filled with cations. 
E) cations occupy standard atomic positions in the unit cell, not the holes.

Exam 12: Solids: Crystals, Alloys, and Polymers

Compare the packing efficiency of face-centered cubic gold and face-centered cubic sodium chloride considering all the atoms.

Which statement does not describe a simple cubic unit cell?

In the sodium chloride unit cell, the chloride ions form a cube in which each side is arranged like the following figure. The circles represent the positions of the chloride ions on one square face of the cube. All the other faces are the same. What is the name of this unit cell?

In interstitial alloys, a maximum (  1) atomic radius ratio would indicate an atom would likely fit in what type of hole(s)?

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) crystallizes as a simple cubic unit cell with an edge length of 335 pm. What is the atomic radius of polonium?

Which of the following unit cells has the highest packing efficiency?

A cubic closest-packed structure has hexagonally arranged layers of atoms stacking in the series ________

What type of hole is depicted below? The gray circle represents the top layer.

A rock salt structure has smaller ions in ________

Draw a few subunits of the polymer derived from the following molecule.

Iron (Fe) crystallizes as a body-centered unit cell with an edge length of 287 pm. What is the atomic radius of iron in picometers?

At a historic Civil War battleground, a stack of cannonballs looked like the picture below on the far left. Removing the top cannonball resulted in the middle view, and removing the next layer resulted in the view on the right. What sort of packing was used in stacking the cannonballs?

Gold has a face-centered cubic structure with a unit cell edge length of 407.8 pm. What is the contribution to the density from each individual gold atom?

What type of hole is depicted below? The gray circles represent the top layer.

An atom in a particular unit cell has 6 nearest neighbor atoms around it. Which unit cell(s) are possible?

Compare the packing efficiency of face-centered cubic copper and simple cubic polonium.

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

The face-centered cubic unit cell has ________ tetrahedral holes.

Sphalerite (ZnS) is the chief ore of zinc. In the unit cell of sphalerite, ________

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

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Additional Aqueous Equilibria: Chemistry and the Oceans

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Electrochemistry: The Quest for Clean Energy

Nuclear Chemistry: Applications to Energy and Medicine

Organic and Biological Molecules: the Compounds of Life

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

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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.