Deck 18: The Solid State a Particulate View

Question 1

Which of the following is NOT an example of an ore?

A)hematite (Fe₂O₃)
B)chalcocite( Cu₂S)
C)argentite (Ag₂S)
D)chalcopyrite (CuFeS₂)
E)quartz (SiO₂)

Answer 1

quartz (SiO₂)

Question 2

Which of the following statements is NOT true about a crystallographic unit cell?

A)It repeats throughout a crystalline structure in three dimensions.
B)It fills all the space in the crystalline lattice.
C)Its dimensions can be measured with X-rays.
D)It always has corners with 90 $\degree$ angles.
E)It represents the smallest repeating unit in the crystal.

Answer 2

It always has corners with 90 $\degree$ angles.

Question 3

Which of the following statements regarding crystalline solids is NOT correct?

A)There is long-range, three-dimensional order in the arrangements of its constituent particles.
B)They are composed of regular repeating units called unit cells.
C)Atoms, molecules, or ions can form the crystalline lattice.
D)There is no empty space in a perfect crystalline solid.
E)All of the above are correct.

Answer 3

There is long-range, three-dimensional order in the arrangements of its constituent particles.

Question 4

Iron exhibits polymorphism, the ability of a solid material to exist in more than one crystal form.At low to moderate temperatures, it adopts a bcc structure; at temperatures above 913 $\degree$ C, it adopts an fcc structure.Silicon carbide also has polymorphs, including the wurtzite form with abab packing and the sphalerite form with abcabc packing.Which of the following statements is NOT correct?

A)The bcc and fcc forms of iron probably have the same densities.
B)The packing efficiency of iron atoms in the bcc form is lower than that of the fcc form.
C)The two silicon carbide polymorphs probably have the same densities.
D)The packing efficiencies of the two silicon polymorphs are probably the same.
E)Both SiC polymorphs are based on hexagonal packing of atoms.

Question 5

In the sodium chloride unit cell, the chloride ions form a cube in which each side is arranged as in 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?

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

Question 6

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?

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

Question 7

Which of the following have the highest packing efficiency?
I.simple cubic
II.body-centered cubic
III.face-centered cubic
IV.hexagonal closest packed

A)I and II
B)II and III
C)II and IV
D)I and III
E)III and IV

Question 8

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

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

Question 9

Polonium crystallizes in a simple cubic pattern.How many polonium atoms are in each unit cell?

A)1
B)2
C)3
D)4
E)5

Question 10

How many nearest neighbor atoms are there around each atom in a face-centered cubic unit cell?

A)4
B)6
C)8
D)10
E)12

Question 11

Pure solid metals

A)do not crystallize.
B)are amorphous.
C)often crystallize in closest-packed structures.
D)often crystallize in very complex unit cells.
E)crystallize in a wide variety of structures.

Question 12

How many nearest neighbor atoms are there around each atom in a simple cubic unit cell?

A)4
B)6
C)8
D)10
E)12

Question 13

How many nearest neighbor atoms are there around each atom in a body-centered cubic unit cell?

A)4
B)6
C)8
D)10
E)12

Question 14

Which of the following can contain only an element of a single type?

A)metal
B)alloy
C)molecular solid
D)ionic solid
E)ceramic

Question 15

Which of the following is NOT a common characteristic of a metal?

A)shiny appearance
B)high electrical conductivity
C)high thermal conductivity
D)malleability
E)brittleness

Question 16

Which of the following unit cells has the lowest 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 17

In which of the following is (are) the packing efficiency(ies) the lowest?
I.tungsten, bcc
II.titanium, hcp
III.nickel, fcc
IV.polonium, sc

A)I
B)II
C)III
D)IV
E)III and IV

Question 18

The face-centered cubic structure is also known as

A)cubic closest-packed.
B)hexagonal closest-packed.
C)square closest-packed.
D)spherical closest-packed.
E)none of the above, as it is not a closest-packed pattern.

Question 19

Which of the following unit cells has the highest 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 20

The two types of closest-packed lattices are

A)cubic closest-packed and face-centered cubic.
B)cubic closest-packed and hexagonal closest-packed.
C)cubic closest-packed and square closest-packed.
D)cubic closest-packed and pyramidal closest-packed.
E)square closest-packed and hexagonal closest-packed.

Question 21

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?

A)15.78 g/cm³
B)19.30 g/cm³
C)9.648 g/cm³
D)4.824 g/cm³
E)11.60 g/cm³

Question 22

Which unit cell contains the most atoms?

A)fcc
B)bcc
C)simple cubic
D)both fcc and bcc
E)None of the above, as fcc, bcc, and simple cubic contain the same number of atoms.

Question 23

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

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

Question 24

Sodium (Na, 22.99 g/mol) and potassium (K, 39.10 g/mol) both adopt a bcc structure.The radius of a potassium atom is approximately 1.23 times that of a sodium atom, and potassium's bulk density is about 1.98 g/cm³.What is the approximate density of sodium?

A)1.09 g/cm³
B)1.61 g/cm³
C)1.70 g/cm³
D)2.17 g/cm³
E)2.44 g/cm³

Question 25

Copper crystallizes in a face-centered cubic pattern.How many copper atoms are in each unit cell?

A)2
B)4
C)8
D)12
E)14

Question 26

Iron (Fe) has a density of 7.87 g/cm³ and crystallizes in a body-centered cubic structure.What is the atomic radius of iron?

A)99.0 pm
B)114 pm
C)124 pm
D)143 pm
E)255 pm

Question 27

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?

A)119 pm
B)168 pm
C)266 pm
D)335 pm
E)419 pm

Question 28

If a face-centered cubic unit cell has a volume of 1.45 * 10⁸ pm³ and the atoms at the corners touch the atom on the face, what must be the atom's radius?

A)186 pm
B)388 pm
C)4240 pm
D)125 pm
E)1050 pm

Question 29

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

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

Question 30

Which of the following can be varied to change the physical properties of an alloy?
I.the elements used
II.the proportions used
III.the sites that each element occupies

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

Question 31

If the unit cell of copper (Cu) has an edge length of approximately 362 pm and the radius of a copper atom is approximately 128 pm, what is the probable crystal structure of copper?

A)simple cubic
B)side-centered cubic
C)body-centered cubic
D)face-centered cubic
E)more information is required

Question 32

An unknown metal with an fcc structure has a density of 10.5 g/cm³, and the edge length of the unit cell is 409 pm.What is the probable identity of the metal?

A)Silver (Ag)
B)Manganese (Mn)
C)Aluminum (Al)
D)Samarium (Sm)
E)More information is required.

Question 33

Which of the following refers to an alloy in which the composition is variable and the elements have comparable radii (within 15%)?

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

Question 34

If a body-centered cubic unit cell has a volume of 1.45 * 10⁸ pm³, what must be the dimension of the cube's edge?

A)1.13*10⁸ pm
B)1.10 * 10² pm
C)1.20 * 10⁴ pm
D)525 pm
E)367 pm

Question 35

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

A)21.44 g/cm³
B)26.06 g/cm³
C)13.10 g/cm³
D)6.550 g/cm³
E)19.28 g/cm³

Question 36

If tungsten (W) adopts a bcc structure with a unit cell edge length of 321 pm, what is the length of the body diagonal across the unit cell (from opposite corners on opposite faces)?

A)731 pm
B)454 pm
C)139 pm
D)556 pm
E)185 pm

Question 37

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

A)99.0 pm
B)114 pm
C)124 pm
D)143 pm
E)256 pm

Question 38

Aluminum (Al) has a density of 2.70 g/cm³ and crystallizes in a face-centered cubic structure.What is the unit cell edge length?

A)2.47 *10^-3 pm
B)40.0 pm
C)405 pm
D)321 pm
E)255 pm

Question 39

Iron crystallizes in a body-centered cubic pattern.How many iron atoms are in each unit cell?

A)1
B)2
C)4
D)8
E)9

Question 40

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?

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

Question 41

In a two-component alloy, the more abundant metal can be thought of as the solvent while the less abundant metal can be thought of as the solute.Which of the following is an explanation of why an alloy is often harder than either of the pure elements?
I.In a homogenous substitutional alloy, the solute atoms slightly distort the crystal structure, making it hard for atoms to slip past one another.
II.In a heterogeneous alloy, small regions rich in the solute atom can disrupt the crystal lattice, making it hard for atoms to slip past one another.
III.When solute atoms occupy interstitial sites, they can prevent the atoms in the crystal structure from slipping past one another.

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

Question 42

The higher the carbon content in steel,

A)the stronger and more malleable it is.
B)the stronger and more brittle it is.
C)the weaker and more malleable it is.
D)the weaker and more brittle it is.
E)any of these, depending on the formula of the interstitial compound.

Question 43

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

A)low density.
B)low cost.
C)high luster.
D)high thermal conductivity.
E)high conductivity.

Question 44

In addition to carbon and iron, stainless steel contains

A)teflon and polyethylene.
B)gold and silver.
C)copper and nickel.
D)chromium and nickel.
E)platinum.

Question 45

Which of the following refers to an alloy in which the composition of the elements is variable, and one element must have a much smaller radius than the other?

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

Question 46

Molecular orbital theory can be applied

A)only to two adjacent metal atoms.
B)only to a few metal atoms that are very close to each other.
C)to any number of metal atoms.
D)to nonmetals only-not to metals.
E)to nonmetals and ionic bonds only-not to metals.

Question 47

Mangalloy is a nonmagnetic steel with extreme antiwear properties.It contains approximately 0.8-1.25% carbon (r = 77 pm) and 11-15% manganese (r =127 pm), along with iron (r = 126 pm). Mangalloy is

A)a substitutional alloy.
B)an interstitial alloy.
C)both an interstitial and substitutional alloy.
D)a colloidal alloy.
E)an intermetallic compound.

Question 48

Which of the following is NOT associated with the production of iron from iron ore in blast furnaces?

A)Iron ore, coke, and limestone are used.
B)Solid by-products collect on top of molten iron, which is removed from the bottom of the reaction vessel.
C)Molten iron crystallizes at its melting point of 1538C in a bcc structure but then undergoes a phase transition at around 139011eed92d_389f_8cc5_a0ba_9557e4654adf_TB6562_11C to an fcc structure.
D)Limestone (CaCO₃) decomposes to form lime (CaO), which can react with silica impurities (SiO₂) in the iron ore.
E)The carbon content is reduced by heating the impure molten iron in a second furnace to temperatures above 160011eed92d_389f_8cc5_a0ba_9557e4654adf_TB6562_11C.

Question 49

Solder is a fusible metal alloy that is used to join together metal wires or work pieces.Old-style solder was often 60% tin( r = 140 pm) and 40% lead (r = 154 pm).Heating the solder caused it to melt; upon cooling, small sites would develop that were richer in Pb, which has a higher melting point than Sn. Cooled solder is thus best classified as

A)a homogeneous alloy.
B)a heterogeneous alloy.
C)an interstitial alloy.
D)a colloidal alloy.
E)an intermetallic compound.

Question 50

Nickel aluminide, Ni₃Al, is sometimes used as a strengthening constituent in high-temperature nickel-base superalloys.It is approximately 13.3% aluminum (r = 143 pm) and 86.7% nickel (r = 124 pm).Ni₃Al is best classified as

A)a substitutional alloy.
B)an interstitial alloy.
C)both an interstitial and substitutional alloy.
D)a colloidal alloy.
E)an intermetallic compound.

Question 51

Stainless steel is less susceptible to rusting than iron because

A)it is coated with plastic.
B)the added metals in the alloy are oxidized more easily, forming 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 52

In comparing the density of bronze composed of 20% tin (r =140 pm, 7.37 g/cm3) to the density of pure copper (r =128 pm, 8.92 g/cm³),

A)the density of the bronze is lower.
B)the density of the bronze is higher.
C)the density of the bronze is the same.
D)the density of the bronze depends on whether the tin or the copper occupies holes.
E)It cannot be determined as only the 1:1 intermetallic compound of tin and copper has ever been observed.

Question 53

Boron( r = 88 pm) is sometimes added to steel alloys as a hardening agent.Suppose one alloy contains approximately one B atom for every 1920 Fe atoms(r = 126 pm).Which of the following statements regarding the boron in alloy is correct?

A)Boron probably occupies a small fraction of octahedral holes in the iron crystal lattice.
B)Boron probably occupies a small fraction of tetrahedral holes in the iron crystal lattice.
C)Boron probably occupies a small fraction of cubic holes in the iron crystal lattice.
D)Boron probably replaces a small fraction of the iron atoms in the crystal lattice.
E)The alloy is approximately 0.05% boron by mass.

Question 54

In a two-component alloy the more abundant metal can be thought of as the solvent while the less abundant metal can be thought of as the solute.Which of the following would NOT change the orientation of atoms in the solvent's unit cell?
I.a solute with the same atomic radius as the solvent
II.a solute that was sufficiently small to fit into holes in the solvent's unit cell
III.a solvent that was sufficiently small to fit into holes in the solute's unit cell

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

Question 55

Aluminum is resistant to corrosion because of

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 56

Band theory of bonding in solids

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 these are correct.

Question 57

Terne, originally an alloy of lead (Pb; r = 154 pm, fcc) and tin( Sn; r =140 pm), appears to contain approximately 7 tin atoms for every 16 lead atoms.Which of the following statements regarding the alloy is correct?

A)It is probably an interstitial alloy with tin occupying some of the octahedral holes.
B)It is probably an interstitial alloy with tin occupying some of the tetrahedral holes.
C)It is probably an interstitial alloy with tin occupying some of the cubic holes.
D)It is probably a substitutional alloy.
E)It is approximately 70% Pb and 30% Sn.

Question 58

A bronze alloy is composed of 10% tin( r = 140 pm) and 90% copper( r =128 pm).It can be classified as

A)a substitutional alloy.
B)an interstitial alloy.
C)a doped semiconductor.
D)a colloidal alloy.
E)an intermetallic compound.

Question 59

Suppose that approximately one-third of the octahedral holes in the fcc lattice of iron (Fe; r= 126 pm) is occupied by a carbon atom (C; r = 77 pm).Which of the following is its probable composition?

A)FeC
B)FeC₃
C)Fe₃C
D)Fe₃C₃
E)Carbon cannot occupy the octahedral holes in the iron crystal lattice.

Question 60

The bonding in solid-state metals can be described as

A)nonexistent.
B)a covalent network.
C)highly directional.
D)an electron sea.
E)ionic.

Question 61

Light-emitting diodes contain semiconductors that emit light when a current is passed through them.What is the key factor in determining the wavelength of the emitted light in an LED?

A)the width of the valence band
B)the width of the conduction band
C)the width of the band gap
D)the magnitude of the current
E)the type of semiconductor p vs.n)

Question 62

Metalic solids are good conductors of electricity because

A)they are easily ionized.
B)their valence electrons are not localized.
C)they are easily reduced and oxidized.
D)they can be drawn into wires.
E)they are ductile.

Question 63

The band structure of semiconductors differs from that of metal conductors in that

A)metal bands are relatively empty while semiconductor bands are nearly full.
B)metal bands are nearly full while semiconductor bands are relatively empty.
C)metal conduction bands are lower in energy than valence bands while semiconductor conduction bands are higher in energy than valence bands.
D)metal conduction bands are higher in energy than valence bands while semiconductor conduction bands are lower in energy than valence bands.
E)valence bands in metals are either partially empty or overlap with conduction bands while these bands in semiconductors are separated in energy by a small gap.

Question 64

What is the probable origin of the electrical conductivity of cadmium when its electron configuration is [Kr]4d 105s2?

A)One electron on each atom is promoted to a 5p orbital when many cadmium atoms interact, and the electrons are free to move.
B)Empty 5p orbitals can be combined to form a conduction band that overlaps the valence band, and electrons that move from the valence band to the conduction band are mobile.
C)Pairs of mobile electrons form when many cadmium atoms interact.
D)Cadmium has a very low ionization energy, which makes the valence electrons highly mobile.
E)4d orbitals mix with 5s orbitals, creating empty energy bands in which electrons can move.

Question 65

The hybridization of carbon in graphite is

A)sp.
B)both sp² and sp³.
C)sp².
D)sp³.
E)dsp³.

Question 66

Based on the approximate wavelength of light emitted by the following materials, which one has the smallest band gap?

A)aluminum nitride, $\lambda$ = 206 nm
B)gallium nitride, $\lambda$ = 371 nm
C)indium nitride, $\lambda$ = 620 nm
D)boron-doped diamond, $\lambda$ = 675 nm
E)nitrogen-doped diamond, $\lambda$ = 425 nm

Question 67

Which of the following can be used to increase the conductivity of any semimetal? I.adding an element with one additional valence electron
II)adding an element with one less valence electron
III)lowering the temperature

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

Question 68

Which element would be used to dope germanium (Ge) to produce an n-type semiconductor?

A)Ga
B)Sn
C)Si
D)As
E)Cu

Question 69

The most common allotrope of carbon is

A)coal.
B)graphite.
C)soot.
D)diamond.
E)fullerene.

Question 70

An approximately spherical allotrope of carbon containing 60 or 70 atoms is

A)spherohexadecalene and spheroheptadecalene.
B)spheralene-60 and spheralene-70.
C)fullerene.
D)graphitolene.
E)soccerene.

Question 71

When silicon (Si) is doped with phosphorus (P), it produces a(n) _______-type semiconductor.

A)p
B)n
C)q
D)np
E)No semiconductor will be produced.

Question 72

Which of the following statements regarding band theory and solid-state bonding in lithium is NOT correct?

A)The 2s orbitals on lithium atoms overlap to form molecular orbitals.
B)Many lithium atoms are required for the overlap of atomic orbitals to form continuous bands of energies.
C)The metallic bonds holding lithium atoms together in the solid are weak.
D)The valence band and the conduction band created by the overlap of atomic orbitals are both half full.
E)Lithium's conductivity is explained by the proximity of unoccupied orbitals in the conduction band to the occupied orbitals in the valence band.

Question 73

Considering the elements C, Si, Ge, and Sn, which are semiconductors?

A)C and Si
B)Si and Ge
C)Ge and Sn
D)None of these elements are semiconductors unless a dopant is added.
E)All of these elements are semiconductors.

Question 74

When a small amount of silver is added to zinc sulfide as an activator, the band gap of the resulting material is approximately 266 kJ/mol.If this material were used as a light-emitting diode, what color of light would be emitted?

A)ultraviolet
B)infrared
C)red
D)yellow
E)blue

Question 75

When silicon (Si) is doped with gallium (Ga), electrical conductivity increases because gallium

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

Question 76

Which element could be used to dope silicon Si) to produce a p-type semiconductor?

A)boron (B)
B)carbon (C)
C)aluminum (Al)
D)phosphorus (P)
E)germanium (Ge)

Question 77

GaAs and AlGaAs₂ are used in what type of semiconductor device?

A)light-emitting diode (LED)
B)sound-emitting
C)np
D)They are not semiconductors.
E)dual voltage

Question 78

Structural forms of an element in which the atoms are bonded together in a different manner are called

A)polymers.
B)allotropes.
C)isotopes.
D)isoforms.
E)polymorphs.

Question 79

When germanium (Ge) is doped with gallium (Ga), it produces a(n)______ -type semiconductor.

A)p
B)n
C)q
D)np
E)No semiconductor will be produced.

Question 80

Electrical and thermal conductivity in metals is

A)explained by a dipolar coupling model.
B)explained by band theory.
C)explained by ionic bonding.
D)explained by temporary ionization.
E)a function of the level of contamination by excess electrons.