Q: Silver has a face-centered cubic (FCC) structure. If the atomic radius of silver is 144 pm, what is the length of the edge of the unit cell?

$$a = 2 \sqrt{2} \times 144\ \mathrm{pm} = 407\ \mathrm{pm}$$

Q: Which of the following is the correct formula for calculating the density of a unit cell?

$$\text{Density} = \frac{Z \times M}{N_A \times a^3$}$$

Question 1

Which of the following statements best describes the bonding in a metallic solid according to the electron sea model?

Accepted Answer

Electrons are delocalized and move freely throughout the lattice, allowing for electrical conductivity.

Question 2

Diamond and graphite are both allotropes of carbon. Which property is unique to graphite compared to diamond?

Accepted Answer

Electrical conductivity due to delocalized electrons between layers.

Question 3

A compound forms a crystal structure with cations (M) at each corner and one on each face. Eight anions (X) occupy the holes in the structure. What is the formula of the compound?

Accepted Answer

$$MX_2$$

Question 4

Which of the following best explains why ionic solids tend to have high melting points?

Accepted Answer

They have strong electrostatic attractions between oppositely charged ions.

Question 5

How many atoms are present in a body-centered cubic (BCC) unit cell?

Accepted Answer

2

Question 6

Silver has a face-centered cubic (FCC) structure. If the atomic radius of silver is 144 pm, what is the length of the edge of the unit cell?

Accepted Answer

$$a = 2 \sqrt{2} 	imes 144\ \mathrm{pm} = 407\ \mathrm{pm}$$

Question 7

Which of the following best describes the structure of a simple cubic unit cell?

Accepted Answer

Atoms are located only at the corners of the cube.

Question 8

Which property is most characteristic of molecular solids?

Accepted Answer

Low melting point and softness.

Question 9

Which of the following best describes the coordination number in a face-centered cubic (FCC) unit cell?

Accepted Answer

12

Question 10

Which of the following statements about the band theory of solids is correct?

Accepted Answer

In insulators, the band gap between the valence and conduction bands is large, preventing electron flow.

Question 11

Which of the following is the correct formula for calculating the density of a unit cell?

Accepted Answer

$$	ext{Density} = \frac{Z 	imes M}{N_A 	imes a^3$}$$

Question 12

Which of the following best explains why graphite conducts electricity while diamond does not?

Accepted Answer

Graphite has delocalized electrons between layers, while diamond has localized electrons in covalent bonds.

Question 13

Which of the following is NOT a property of ionic solids?

Accepted Answer

Electrical conductivity in the solid state

Question 14

Which of the following best describes the process of doping in semiconductors?

Accepted Answer

Adding impurities to increase the number of electrons in the conduction band.

Question 15

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

Accepted Answer

Face-centered cubic

Question 16

Which of the following is the correct expression for the lattice energy ($$LE) $$using the Born-Haber cycle?

Accepted Answer

$$LE = \Delta H_{f} - (	ext{Sublimation} + 	ext{Ionization} + 	ext{Dissociation} + 	ext{Electron Affinity})$$

Question 17

Which of the following best describes the arrangement of atoms in a body-centered cubic (BCC) unit cell?

Accepted Answer

Atoms at the corners and one atom at the center of the cube.

Question 18

Which of the following solids is most likely to be malleable and ductile?

Accepted Answer

Metallic solid

Question 19

Which of the following is a property of covalent network solids such as diamond?

Accepted Answer

High melting point and hardness

Chapter 12 Student Notes

Guida di studio - Domande di pratica

Study guide - Flashcard