C2

Question 1

Why do metals conduct electricity ( 3 marks)

Answer 1

Metal is a giant structure of delocalised electrons held together with metallic bonding
The delocalised electrons carry electrical charge throughout the whole structure this makes metals good conductors of heat

Question 2

Two differences between the physical properties between Group 1 and transition metals

Answer 2

Trans - high mp
Group 1 - low mp
Group 1 - forms colourless compound
Trans - colourful compound

Question 3

Shape of buckminsterfullerene

Answer 3

hollow sphere

Question 4

What are allotropes

Answer 4

Different structural forms of the same elements in the same physical state

Question 5

Give three uses of fullerene

Answer 5

lubricants
catalysts
drug delivery

Question 6

Explain why diamond has a high melting point (3 marks)

Answer 6

Giant covalent structure made up of carbon atoms
Each form four covalent bonds - makes diamond really hard
Strong covalent bonds take lots of energy to break

Question 7

Why doesn’t diamond conduct electricity

Answer 7

No free electrons or ions

Question 8

Explain why graphite is soft and slippery (4 marks)

Answer 8

Each carbon atom only forms three covalent bonds
Creating sheets of carbon atoms arranged in hexagons
No covalent bonds between the layers - held together weakly - free to move

Question 9

What are the limitations of the ball and stick model ( 3 marks)

Answer 9

Suggests that the crystal extends beyond what’s shown in the diagram
Model isn’t to scale - relative sizes of ions may not be shown
In reality there aren’t any gaps between the ions

Question 10

What are the limitations of the dot and cross diagram ( 1 mark)

Answer 10

they do not show the 3D arrangement of ions in the lattice.

Question 11

What are the limitations of two and three dimensional diagrams of a ionic lattice (2 marks)

Answer 11

Two-dimensional they cannot show the 3D structure of the lattice.
Three-dimensional difficult to accurately show the position of each ion in the lattice.

Question 12

When working out empirical formula do you count the atoms or working out the charges using outer electrons

Answer 12

Workout charges using outer electrons

Question 13

Limitation of your standard ‘gas liquid solid ‘ diagrams ( 3 marks)

Answer 13

Model there are no forces,
That all particles are represented as spheres and
That the spheres are solid.

Question 14

Name the 7 simple molecular substances

Answer 14

Chlorine
Nitrogen
Water
Hydrogen Chloride
Oxygen
Methane
Hydrogen

Question 15

Explain why graphene can conduct electricity and what can it be used for ( 3 marks)

Answer 15

One sheet of carbon atoms joined together in hexagons
Contains delocalised electrons so can conduct electricity through the whole structure
Electronics and composites

Question 16

Explain why graphite conducts electricity and thermal energy ( 2 marks)

Answer 16

Three out of each carbon’s four electrons are used in bonds - each carbon atom has one free electron that is delocalised and is free to move

Question 17

What can fullerene form

Answer 17

Nanotubes - tiny carbon cylinders

Question 18

Three properties of fullerene

Answer 18

Ratio length:diameter is very high
Can conduct both electricity and thermal energy
High tensile strength

Question 19

What two things can fullerene be used for

Answer 19

Electronics or to strengthen materials without adding much weight