11D - Solids

Question 1

Def: What are the two types of solids? What are their orders?

Answer 1

Crystalline: Ordered matrix, cleave along well-defined plane
Amorphous: Short-range order, varying properties, disored

Question 2

Theory: What are the 3 types of crystalline solids?

Answer 2

1. Molecular
2. Ionic
3. Atomic

Question 3

Def: What is molecular solid? Properties?

Answer 3

Composite units are molecules.
LDF’s, D-D, H-B
Low bp and mp
Electrical insulators
Soluble in similar solvents

Question 4

Def: What is an ionic solid? Properties?

Answer 4

Composite units are cations and anions.
Electrostatic attraction, non-drectional
Hard
Brittle
High mp and bp
E and T insulators
Some soluble in polar solvents

Question 5

Def: What is a atomic solid? What are the three types.

Answer 5

Composite units are atoms.
1. Metallic
2. Network Covalent
3. Non-bonding

Question 6

Def: What is metallic solid? Properties?

Answer 6

Metal ions in a sea of valence electrons.
Soft
Ductile
Malleable
Varying mp and bp
Many react in acid
T and E insulator

Question 7

Def; What is a network covalent solid (NCS)? Properties?

Answer 7

Covalent bonds and LDF’s.
Hard and brittle
Very high bp and mp
Insulator and semi-conductors
Insouble

Question 8

Def: What is a crystalline solid and why do they form? What are the two parts of a crystal?

Answer 8

When letting liquid cool to solid, particles rearrange for max IF’s and therefore lowest E, creating a crystal solid.
Lattice: Repeating 3-d pattern of points in space (theoretical) (like cubes put together)
Basis: chemical unit (atom, molecule, etc.), one of each at every lattice point

Question 9

Theory: What are the three cubic unit cells (out of 14)?

Answer 9

1. Simple cubic (SC)
2. Body-Centered (BCC)
3. Face-Centered (FCC)

Question 10

Def: What is a lattice point and a lattice plane?

Answer 10

Lattice point: Each particle in a unit cell
Plane: Planes connecting equivalent points throughout the lattice

Question 11

Theory: What are the rules for the number of particles in a unit cell?

Answer 11

1/8 in each corner
1/2 on each face
1/4 on each edge (not applicable)
1 in center

Question 12

Def: What is a coordination number? Is there empty space unit cells?

Question 13

Def: What is a SC made of? What is the edge length in comparison to radius? What is it’s volume?

Answer 13

8 corners, 1 particle.
Edge length = 2r
V = 8*r^3

Question 14

Def: What is a BCC made of? What is the edge length in comparison to radius? What is it’s volume?

Answer 14

8 corners, 1 center, 2 particles.
Edge length = 4/sqrt(3)r
V = r^3(16/3)^(3/4)

Question 15

Def: What is a FCC made of? What is the edge length in comparison to radius? What is it’s volume?

Answer 15

8 corners, 6 faces, 4 particles.
Edge length = 2/sqrt(2)r
V = rsqrt(8)

Question 16

Theory: How do determine packing efficiency / percent volume of atom? Formula for volume of atoms and and percent volume of atom?

Answer 16

V-atoms = n((4/3)*r^3), where n is number of atoms in the units cell.
%V-atom = v-atom / v-unit cell * 100%