Deck 21: Structure and Bonding in Solids

Question 1

Which of the following has 3 non-identical 2-fold rotation axes?

A) A cereal box
B) A five pointed star
C) A cube
D) An isosceles triangle
E) An equilateral triangle

Answer 1

A

Question 2

Which of the following has the most mirror planes?

A) A cereal box
B) A five pointed star
C) A cube
D) An isosceles triangle
E) An equilateral triangle

Answer 2

C

Question 3

Which of the following has exactly one two-fold rotation axis?

A) A cereal box
B) A five pointed star
C) A cube
D) An isosceles triangle
E) An equilateral triangle

Answer 3

D

Question 4

Which of the following have the same number of rotation axes and mirror planes?

A) Cereal box and a cube
B) A five pointed star and an isosceles triangle
C) An isosceles triangle and a five pointed star
D) A pentagon and an isosceles triangle
E) A pentagon and a five pointed star

Question 5

Of the seven crystal systems, which has the lowest symmetry requirements?

A) hexagonal
B) cubic
C) triclinic
D) tetragonal
E) orthorhombic

Question 6

The tetragonal crystal system minimally requires one four-fold rotation axis. Which of the following conditions on unit-cell edges and angles would satisfy this?

A) a=b=c, a=b=g=90°
B) a=b¹c, a=b=g=90°
C) a=b=c, a=b=g¹90°
D) a and b
E) a and c

Question 7

Assuming that atoms are solid spheres, what percentage of space is consumed by the atoms in the simple cubic primitive cell?

A) 48%
B) 52%
C) 68%
D) 26%
E) 32%

Question 8

Assuming that atoms are solid spheres, what percentage of space is consumed by the atoms in the body-centered cubic primitive cell?

A) 48%
B) 52%
C) 68%
D) 26%
E) 74%

Question 9

Assuming that atoms are solid spheres, what amount of free space is found in the face-centered cubic primitive cell?

A) 48%
B) 52%
C) 68%
D) 26%
E) 32%

Question 10

Which of the following is not an acceptable location for an atom in a side-centered primitive cell?

A) (1,1,0)
B) (1, ,0)
C)
D) all of the above
E) none of the above

Question 11

Exhibit 21-1
The following question(s) pertain to Gallium which has a simple cubic unit cell. It has a molar mass of 69.72 g·mol^-1 and a density of 5.91 g·cm^-3.
Refer to Exhibit 21-1. How many atoms are contained within a single Gallium unit cell?

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

Question 12

Exhibit 21-1
The following question(s) pertain to Gallium which has a simple cubic unit cell. It has a molar mass of 69.72 g·mol^-1 and a density of 5.91 g·cm^-3.
Refer to Exhibit 21-1. What is the diameter of a single Gallium atom?

A) 2.70 Å
B) 1.35 Å
C) 1.63 Å
D) 2.44 Å

Question 13

Exhibit 21-2
The following question(s) pertain to Palladium which has a face-centered cubic unit cell. It has a molar mass of 106.4 g·mol^-1 and a density of 7.14 g·cm^-3.
Refer to Exhibit 21-2. How many atoms are contained within a single palladium unit cell?

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

Question 14

Exhibit 21-2
The following question(s) pertain to Palladium which has a face-centered cubic unit cell. It has a molar mass of 106.4 g·mol^-1 and a density of 7.14 g·cm^-3.
Refer to Exhibit 21-2. What is the radius of a single palladium atom?

A) 2.70 Å
B) 1.22 Å
C) 1.64 Å
D) 2.44 Å

Question 15

Exhibit 21-3
The following question(s) pertain to Iron which has a body-centered cubic unit cell. It has a molar mass of 55.847 g·mol^-1 and a density of 7.86 g·cm^-3.
Refer to Exhibit 21-3. How many atoms are contained within a single iron unit cell?

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

Question 16

Exhibit 21-3
The following question(s) pertain to Iron which has a body-centered cubic unit cell. It has a molar mass of 55.847 g·mol^-1 and a density of 7.86 g·cm^-3.
Refer to Exhibit 21-3. What is the radius of a single iron atom?

A) 2.55 Å
B) 1.24 Å
C) 1.94 Å
D) 1.05 Å

Question 17

An element crystallizes in a body-centered cubic lattice, with a = 4.109 Å. If the element has a density of 9.95 g·cm^-3, what is the molar mass of the element?

A) 104 g·mol^-1
B) 208 g·mol^-1
C) 416 g·mol^-1
D) 831 g·mol^-1

Question 18

In crystalline sodium the distance between adjacent layers in a certain set of equally spaced planes of atoms is 4.28 Å. What is the maximum order n for observation of Bragg diffraction using X-rays with a wavelength of 1.936 Å?

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

Question 19

When two metal atoms are brought close together

A) an electron is transferred from one atom to the next resulting in a coulombic attraction.
B) all of the electrons are shared between the two atoms.
C) Groups of closely spaced molecular orbitals are formed.
D) b and c
E) none of the above

Question 20

Covalent crystals are

A) soft and malleable.
B) hard and brittle.
C) have low melting points.
D) a and c
E) b and c

Question 21

Molecular crystals are

A) soft and malleable
B) hard and brittle
C) have low melting points
D) a and c
E) b and c

Question 22

Molecular crystals are held in lattice sites by

A) covalent bonds.
B) ionic bonds.
C) intermolecular forces.
D) large molecular orbitals that span many lattice sites.
E) a and c

Question 23

Which of the following is a metalloid?

A) Al
B) Ge
C) As
D) All of the above
E) None of the above

Question 24

The hybridization of carbon in graphite is ______ while in diamond it is _______.

A) sp², sp²
B) sp², sp³
C) sp², sp³d
D) sp³, sp³d²
E) None of the above

Question 25

Schottky defects are a result of

A) vacancies in the crystal lattice
B) atoms inserted at interstitial sites
C) electron transfer
D) p-bonding interactions at the surface
E) a and b

Question 26

Frenkel defects are a result of

A) vacancies in the crystal lattice
B) atoms inserted at interstitial sites
C) electron transfer
D) p-bonding interactions at the surface
E) a and b

Question 27

Crystalline substances are _______. Amorphous substances are _______.

A) Isotropic, isotropic
B) Anisotropic, anisotropic.
C) Isotropic, anisotropic.
D) Anisotropic, isotropic.

Question 28

For a face-centered cubic lattice, each lattice point located in the face of the unit cell is shared equally with _____ other cells.

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

Question 29

For a face-centered cubic lattice, each lattice point located in the corner of the unit cell is shared equally with _____ other cells.

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

Question 30

For a body-centered unit cell, each corner contributes _____ lattice points to the unit cell.

A) 1/8
B) 1/4
C) 1/2
D) 1

Question 31

Nonstoichiometric compounds can contain

A) different atomic elements that are not in whole number proportions to each other.
B) identical atoms with different oxidation states.
C) species that, upon reaction, always produce less than the theoretical yield.
D) A and B only
E) none of the above

Question 32

Alloy steels can be described as

A) substitutional
B) amorphous
C) interstitial
D) A and B
E) A and C

Question 33

Amorphous solids may have the following:

A) ionic bonding
B) metallic bonding
C) covalent bonding
D) molecular bonding
E) all of the above