Solid State Chemistry

Question 1

Unit Cell

Answer 1

the smallest and simplest arrangement which is repeated in the lattice

Question 2

A Primitive Unit cell

Answer 2

Contains only 1 particle

or molecule
or element
or atom

Question 3

Simple Cubic

Answer 3

8 x 1/8th Particles = 1 Particle Only

(primitive unit cell)

Diagram

Question 4

BCC

Answer 4

Body Centred Cubic

1 + 8 x 1/8th Particles = 2 Particles

Diagram

Question 5

FCC

Answer 5

Face Centred Cubic

6 x 1/2 + 8x 1/8th = 3 + 1 = 4 Particles

Diagram*

Question 6

Extra ones to know

Answer 6

Face centred on one side / Face only

Rhombohedral

Diagrams

Question 7

Calculating the Length of a Unit Cell

Answer 7

Pythagoras - For a Triangle portion of a Face

a^2 + b^2 = c^2

if given 1 value only for the “c” or hypotenuse
then it means it is a Square = “a” and “b” are equal

you usually get 2 if its not a square.

You may need to look at 3 molecules of the same atom
or 2 different sized atoms

You need to find the Diameter of each atom sometimes it is given as an Area and you have to work back

Question 8

Avogadro’s Constant

Answer 8

For unit cell working out

6. 022x^23
   https: //www.youtube.com/watch?v=qe8GjH-N1FY

Question 9

Avogadro’s Constant

Answer 9

For unit cell working out

6. 022x^23
   https: //www.youtube.com/watch?v=qe8GjH-N1FY

Question 10

Unit Cell Metho

Answer 10

Moles in cm3
Atoms in cm3
Unit Cell in cm3

Question 11

Unit Cell Metho

Answer 11

Moles in cm3
Atoms in cm3
Unit Cell in cm3

Volume of a Unit cell
cm3 / Unit Cell (Volume)

Cube root it = cm /Unit Cell
^^ is Edge length
Convert cm to m
then from m to picometres

1x10^-12 m (1 pm)

Question 12

PM - Picometre

Answer 12

x10^-12 m