Solids

Question 1

Two types of solids

Answer 1

Crystalline, amorphous

Question 2

Solids with a highly regular arrangement of their components. Ex. Diamond, quartz, NaCl

Answer 2

Crystalline solids

Question 3

Solids with considerable disorder in structures. Ex. Plastic, glass, rubber

Answer 3

Amorphous

Question 4

Atoms, ions, or molecules packed in regular geometric arrays are called

Answer 4

Lattice

Question 5

Smallest repeating unit of a lattice

Answer 5

Unit cell

Question 6

Number of nearest neighbor atoms in a lattice

Answer 6

Coordination number

Question 7

Recall summary of unit cells

Answer 7

Recall contribution of atoms on each part of a unit cell

Question 8

Formed when a group MO energy levels with closely spaced energies

Answer 8

Band

Question 9

Valence band: highest energy band

Answer 9

Conduction band: partially filled or empty band where electrons can move

Question 10

Metals are good conductors in lower temp

Answer 10

Semiconductors (mettaloids) are good conductors in higher temp

Question 11

In insulators there is a _____ band gap between valence and conduction bands that prevents the motion of electrons

Answer 11

Large

Question 12

Addition of impurities

Answer 12

Doping

Question 13

Semiconductors whose electrical properties are enhanced by doping

Answer 13

Extrinsic semiconductors

Question 14

____ have small band gap between valence and conduction bands

Answer 14

Semiconductors

Question 15

Elements that exhibit semi-conductive behavior at their pure state are called ____, including Se, Ge, and alpha- Sb

Answer 15

Intrinsic semiconductors

Question 16

The conductivity of intrinsic semiconductors are further enhanced by doping semiconductors with other elements using ____ and ____

Answer 16

N-type and P-type dopants

Question 17

N-type dopants (G15) are capable of doping intrinsic semiconductors because because of their additional _____ relative to the host semiconductor.

Answer 17

Free electron.
Note. > valence electron than the element in focus

Question 18

P-type dopants (G13) provide positive ___for increaing the conductance of semiconductors.

Answer 18

Holes
Note. < valence electron than the element in focus

Question 19

Mixture of metals and another element

Answer 19

Alloy

Question 20

An alloy wherein some of the host metal atoms are replaced by other metal atoms of similar size

Answer 20

Substitutional alloys

Question 21

An alloy that is formed when some of the interstices or holes in the closest packed metal structure are occupied by small atoms

Answer 21

Interstitial alloy

Question 22

Presence of the interstitial atoms changes the proprties of the host metal

Answer 22

Steel is an example of interstitial alloy

Question 23

Solids that are characterized by strong covalent bonding within molecules (IMFA) but relatively weak forces between molecules

Answer 23

Molecular solids. They are relatively soft snd have the lowest melting point

Question 24

Solids that are held together by covalent bonds , and have atoms occupying ghe lattice points

Answer 24

Network Covalent or Atomic Solids. They have the highest melting point and they’re made up of nonmetals

Question 25

Solids that are high melting substances held together by strong electrostatic forces that exist between oppositely charged ions

Answer 25

Ionic solids

Question 26

The structures of most binary ionic solids can be explained by closest packing of spheres. Large anions are packed by either FCC or HCP, while smaller cations fit into holes among the closed packed anions.

Answer 26

Packing is done by maximizing the repulsions amon ions with similar charges.

Question 27

Three types of holes in closest packed structures

Answer 27

Trigonal, tetrahedral, octahedral ions

Question 28

The stronger the bond that holds the solids together the higher the melting point

Answer 28

The smaller size of ion with higher charge the greater the lattice energy

Question 29

___ refers to the change in energy that takes place when separated gaseous ions are packed together to form an ionic solids

Answer 29

Lattic energy

Question 30

The process of considering the component reactions that can be imagined as the individual steps in compound formation

Answer 30

Born-Haber Cycle

Question 31

Reflects the effect of geometry of lattice on the strength of net coloumbic interaction

Answer 31

Madelung constant

Question 32

Recall 7 crystal system Triclinic Monoclinic Orthorhombic Rhombohedral Tetragonal Hexagonal Cubic

Answer 32

CCP- 3 repeating layers HCP- 2 repeating layers

Question 33

Conduct current at one direction, using pn junction as basis.

Answer 33

Diode. Used as rectifiers, voltage regulators, and modulators

Question 34

Formed when semiconductor is exposed to light generating electron-hole pairs, increasing conductivity

Answer 34

Photodiode

Question 35

Allows current to be controlled by a small change in potential difference

Answer 35

Transistors. Used in amplifiers

Question 36

Solubility of salts in water. In general, the difference in size favors solubility in water. The interaction responsible for lattice enthalpy are replaced with hydration enthalpy.

Answer 36

If cation has larger hydration enthalpy than it's anion partner or vice versa, then the dissolution of salt is exothermic

Question 37

Imperfections of structure or composition contained by all solids

Answer 37

Defects

Question 38

Defects that occur in pure substances

Answer 38

Intrinsic

Question 39

Defects that stems from the presence of impurities

Answer 39

Extrinsic

Question 40

Defects that occur at single site

Answer 40

Point defect

Question 41

Defects that occurred in 1, 2 and 3 dimensional. Also gives colors to the gemstones we have.

Answer 41

Extended defects