Giant Covalent Structures and Fullerenes

Question 1

Describe, generally, the bonding in carbon-based giant covalent structures.

Answer 1

All of their carbon atoms are bonded together by strong covalent bonds

Question 2

Give 2 examples of giant covalent substances.

Answer 2

• Diamond
• Graphite

Question 3

Describe the structure of diamond.

Answer 3

Each carbon atom forms four covalent bonds

Question 4

Explain the properties of diamond.

Answer 4

• Has a high melting point because it has many strong covalent bonds which require a lot of energy to break
• Doesn’t conduct electricity because it has no free electrons or ions
• It is really hard as the covalent bonds hold the carbon atoms in a rigid lattice structure
• It is used to strengthen cutting tools because of its hardness

Question 5

Describe the structure of graphite.

Answer 5

Each carbon atom forms three covalent bonds, creating sheets of carbon atoms arranged in hexagons

Question 6

Explain the properties of graphite.

Answer 6

• Has a high melting point because it has many strong covalent bonds which require a lot of energy to break
• Can conduct electricity because each of its carbon atoms have one delocalised electron that can move and carry a charge
• It is soft and slippery because the sheets of carbon atoms are held together weakly, so they are free to move over each other

Question 7

(Exam-style question)

Answer 7

Question 8

Give 2 examples of fullerenes.

Answer 8

• Graphene
• Fullerene C₆₀

Question 9

Explain the properties of graphene.

Answer 9

• Has a high melting point because it has many strong covalent bonds which require a lot of energy to break
• Can conduct electricity because each of its carbon atoms have one delocalised electron that can move and carry a charge
• It is strong as the covalent bonds hold the carbon atoms in a lattice structure

Question 10

Explain the properties of the fullerene ‘C₆₀’.

Answer 10

• Has a low melting point because the weak intermolecular forces holding the molecules together can be broken easily
• It is a poor conductor of electricity as there is little movement of electrons between its molecules
• It is weak because it has a molecular structure, meaning there are weak forces between fullerene molecules