1. Diamond, graphite and graphene are allotropes of which element?

a) Silicon
b) Oxygen
c) Carbon
d) Hydrogen

2. What key structural feature is responsible for diamond's hardness?

a) Weak intermolecular forces between the layers
b) Strong covalent bonds in a tetrahedral arrangement
c) Delocalised electrons allowing the movement of carbon atoms
d) Flat layers of carbon atoms arranged in a hexagonal manner

3. Which property is characteristic of graphite but NOT diamond?

a) High melting point
b) Good thermal conductor
c) Electrical insulator
d) Softness and slipperiness

4. Graphite is able to conduct electricity because it contains electrons between the flat layers of hexagons, these hexagon are composed of carbon atoms.

5. In diamond each carbon atom forms strong covalent bonds but in graphite each carbon atoms only forms covalent bonds.

6. Both diamond and silica (silicon dioxide) share what structural characteristic?

a) Layers of flat hexagonal rings
b) The presence of delocalised electrons
c) Tetrahedral arrangement of atoms
d) Weak intermolecular forces between the carbon atoms

7. Why is graphite soft and used as a lubricant?

a) Because of the strong covalent bonds present in the tetrahedral layers
b) Because of the weak intermolecular bonds between the flat layers of hexagons which allows them to slide
c) Because it has a high melting point
d) Because it has delocalised electrons

8. What forces are present between the flat layers of hexagons in graphite?

a) Strong covalent bonds
b) Ionic bonds
c) Weak intermolecular bonds
d) Hydrogen bonds

9. What type of structure does both diamond and graphite have?

a) Giant covalent structure
b) Small molecular structure
c) Metallic structure
d) Layered structure

10. Why is diamond hard?

a) Because it has weak intermolecular bonding
b) Because it has strong covalent bonds in a symmetrical tetrahedral arrangement
c) Because the carbon atoms are arranged in layers with strong covalent bonds present in each layer
d) Because it has a very high melting and boiling point.