Solid Structures

Question 1

What is the structure of solids?

Answer 1

Ordered and crystalline.

Question 2

Solid Structure depends on:

Answer 2

Taking up max amount of space
Directional forces of particles
Requirement to remain electrically neutral
Relative size of particle

Question 3

Main 3 types of cell

Answer 3

Simple cell
Body centred cubic
Face centred cubic

Question 4

Simple cell

Answer 4

Each corner is a corner of circular atom which will be touching

Question 5

Body centred cubic

Answer 5

Each corner is corner of an atom and in the middle is full atom

Question 6

Face centred cubic

Answer 6

Each corner is corner of an atom and each face has half an atom on it

Question 7

Forces that maintain the structure

Answer 7

van der waals (temporary dipoles)
metallic binding (delocalised electrons)
Ionic bonds (opposite charges)
Covalent bonds (shared electrons)
Hydrogen bonds (Hydrogen attached to electronegative atom)

Question 8

How are atoms structured

Answer 8

Layer will either be a copy of one 2 previous or aim to fill spaces left by previous:
ABA or ABC

Question 9

Coordination number

Answer 9

Number of atoms a given atom will be touching

Question 10

Coordination number for: Simple cell

Answer 10

6

Question 11

Coordination number for: Body centred cubic

Answer 11

8

Question 12

Coordination number for: Face centred cubic

Answer 12

12

Question 13

Side length (volume) for simple cell

Answer 13

2 radii

Question 13

Packing fraction

Answer 13

percentage space in cell taken up by atoms.
Packing fraction = atomic volume/ total volume = atomic volume/(side length)^3

Question 14

Total atoms occupying for simple cell

Answer 14

1 atom

Question 15

Side length (volume) for body centred cubic

Answer 15

((16/3)^(1/2))r,
cube diagonal has 4r length, so can be solved via Pythagoras

Question 16

Total atoms occupying for body centred cubic

Answer 16

2, one in middle and 8*1/8 in corners

Question 17

Side length (volume) for face centred cubic

Answer 17

Face diagonal = 4r
Side calculated by pythagoras

Question 18

Total atoms occupying for face centred cubic

Answer 18

4, half a volume on each face (6) and 1/8th in each corner

Question 19

Coordinate number change for ionic crystals:

Answer 19

There will be 2 coordinate numbers for the cell.
It is equal to number of oppositely charged ions touching an ion

Question 20

Radius change for ionic crystals

Answer 20

We have 2 different sized atomic radii so we use radius ratio = r_smaller/r_larger