Solids Properties

Question 1

What is an amorphous solid?

Answer 1

An irregular solid composed of a non-uniform network of particles

Question 2

What forces hold an amorphous solid together?

Answer 2

Directional covalent bonds

Question 3

Provide examples of an amorphous solid:

Answer 3

Glass, rubber, some plastics

Question 4

What is the hardness of an amorphous solid?

Answer 4

Variable (non-regular bonds, not predictable between solids)

Question 5

What is the melting point of an amorphous solid?

Answer 5

Variable (non-regular bonds, melt at different temperatures)

Question 6

Are amorphous solids conductors?

Answer 6

Poor conductors

Question 7

What is a crystalline solid?

Answer 7

Solid that shows an ordered repeating particle pattern (true solid)

Question 8

What is an atomic solid?

Answer 8

A solid in which atoms (can be of varying elements) occupy positions within a crystalline structure.

Question 9

What is a (covalent) network solid?

Answer 9

A solid composed of repeating covalently bonded atoms.

Question 10

What bonds hold a network solid together?

Answer 10

Directional covalent bonds

Question 11

Provide examples of a network solid:

Answer 11

Diamond (3D), graphite (2D), quartz (SiO2)

Question 12

What are the structural units of a network solid?

Answer 12

Atoms (typically nonmetals)

Question 13

What is the hardness of a network solid?

Answer 13

Usually high, but variable

Question 14

What is the melting point of a network solid?

Answer 14

Usually high, but variable

Question 15

Are network solids conductors?

Answer 15

No, insulators

Question 16

Which is stronger, a 2D or 3D network solid?

Answer 16

3D (also has a higher melting point and hardness e.g. diamond vs. graphite)

Question 17

What is a unit cell?

Answer 17

The simplest repeating part of a crystal

Question 18

What is a metallic solid?

Answer 18

A solid composed of metal atoms in a sea of electrons

Question 19

What forces hold a metallic solid together?

Answer 19

Nondirectional covalent bonds (delocalized valence electrons)

Question 20

Provide examples of a metallic solid:

Answer 20

Iron, Gold, Copper, Steel, Pewter

Question 21

What is an interstitial alloy?

Answer 21

A metallic alloy in which other atoms are placed into the open spaces between metal cations (e.g. carbon in steel)

Question 22

What is a substitutional alloy?

Answer 22

A metallic alloy in which other metallic atoms are introduced into the electron sea (e.g. brass)

Question 23

What are the structural units of a metallic solid?

Answer 23

Metal ions (cations)

Question 24

What is the hardness of a metallic solid?

Answer 24

Alloys (hard)
Pure (soft)

Question 25

What is the melting point of a metallic solid?

Answer 25

Variable, can be incredibly hot (e.g. Tungsten W)

Question 26

Are metallic solids conductors?

Answer 26

Very good conductors of both heat and electricity.

Question 27

What is a group 8A solid?

Answer 27

Solids composed of elements from the noble gases

Question 28

Provide examples of a group 8A solid:

Answer 28

Argon (s)

Question 29

What are the forces holding a group 8A solid together?

Answer 29

London dispersion forces (LDFs)

Question 30

What is the hardness of a group 8A solid?

Answer 30

Soft

Question 31

What is the melting point of a group 8A solid?

Answer 31

Very low

Question 32

What is a molecular solid?

Answer 32

Molecules held in a crystal lattice

Question 33

What forces hold a molecular solid together?

Answer 33

LDFs, dip/dip (sometimes), H-bond (sometimes)

Question 34

Provide examples of a molecular solid:

Answer 34

Ice, dry ice, sugars, O2, NH3, etc.

Question 35

What are the structural units of a molecular solid?

Answer 35

Discrete molecules

Question 36

What is the hardness of a molecular solid?

Answer 36

Soft

Question 37

What is the melting point of a molecular solid?

Answer 37

Low (variable)

Question 38

Are molecular solids conductors?

Answer 38

Poor conductors

Question 39

What is an ionic solid?

Answer 39

A crystal lattice of ions

Question 40

What forces hold an ionic solid together?

Answer 40

Ionic/electrostatic forces

Question 41

Provide examples of an ionic solid:

Answer 41

NaCl, MgO, CaCl2, K2SO4

Question 42

What are the structural units of an ionic solid?

Answer 42

Unit cells of cations and anions

Question 43

What is the hardness of an ionic solid?

Answer 43

Hard but brittle

Question 44

What is the melting point of ionic solids?

Answer 44

Very high

Question 45

What is the solubility of ionic solids?

Answer 45

Usually soluble in water

Question 46

Are ionic solids conductors?

Answer 46

Conductors in liquid phase, non conductors in solid phase