Graphene and Graphite

Question 1

Explain the use of valence electrons for each Carbon atom in a GRAPHITE LAYER

Answer 1

3 used to form covalent bonds with adjacent C atoms (Hexagonal rings)
1 is delocalised and is situated between Graphite layers

Question 2

Why is Graphite able to conduct electricity?

Answer 2

The delocalised electrons between layers carry the electrical charge through the structure

Question 3

Compare the bond energies in-plane and adjacent-to-plane for GRAPHITE, and state the corresponding axis name

Answer 3

HIGH In-Plane A-Axis

LOW Adjacent-To-Plane C-Axis

Question 4

State and explain in-plane properties of graphite

Answer 4

High modulus due to high bond strength
High thermal conductivity due to lattice vibrations
Low thermal expansion due to limited bond stretching (Due to high bond strength)

Question 5

Describe the structure of graphene

Answer 5

A single layer of covalently bonded C atoms
Each C atom forms 3 bonds
A spare valence electron delocalises and is available for conduction in the 3rd dimension

Question 6

Explain the electrical conductivity of graphene

Answer 6

Delocalised electrons allow for the ballistic transport of electrical charge through the structure