Ch 3

Question 1

What is a unit cell?

Answer 1

The smallest repetitive volume, which contains the highest symmetry of a crystal, which reproduces the crystal with only translation

Question 2

What is the unit cell edge length of FCC?

Answer 2

a=2√2R

Question 3

What is the unit cell edge length of SC?

Answer 3

a=2R

Question 4

What is the unit cell edge length of BCC?

Answer 4

a = (4/√3) R

Question 5

Coordination number

Answer 5

The number of nearest neighbors (shortest distance) to each atom in the lattice

Question 6

Dense packing has an ___ structure

Answer 6

ordered

Question 7

Non-dense packing has a __ structure

Answer 7

random

Question 8

Crystalline materials have ___ packing

Answer 8

dense

Question 9

Non-crystalline materials have __ packing

Answer 9

non-dense

Question 10

Why are metallic crystal structures usually densely packed?

Answer 10

Usually 1 element present so atomic radii is same, metallic bonding is non-directional, neighbor distances are small

Question 11

Atomic packing factor

Answer 11

volume of atoms in unit cell/ volume of unit cell

Question 12

What does [uvw] represent?

Answer 12

a specific direction

Question 13

What does <uvw> represent?</uvw>

Answer 13

a family of direction

Question 14

What does (hkl) represent?

Answer 14

a specific plane

Question 15

What does {hkl} represent?

Answer 15

a family of planes

Question 16

1/3(2𝑢 − 𝑣)=

Answer 16

U

Question 17

=1/3(2𝑣 − 𝑢)

Answer 17

V

Question 18

-1/3(u+v)=

Answer 18

T

Question 19

-(U+V)=

Answer 19

T

Question 20

w=

Answer 20

W

Question 21

u=

Answer 21

U-T

Question 22

v=

Answer 22

V-T

Question 23

Isotropic is when material properties

Answer 23

are non-directional (random)

Question 24

Anisotropic is when material properties

Answer 24

are directional