Structure and Bonding of Carbon

1. The figure below shows four structures of carbon. Which structure represents ...a carbon nanotube? ...graphite? ...the first fullerene to be discovered? ...diamond?


Answer: D , A , B , C


2. Diamond is a very hard substance. Give one use of diamond that takes advantage of this property.

Answer: Drill or saw tips.


3. State the property of carbon nanotubes that make them useful in sports equipment.

Answer: They have high tensile strength.


4. Carbon exists in different forms.

a) Describe the structure and bonding in graphene. You may use a diagram in your answer.

Answer: Graphene contains carbon atoms bonded in a single flat layer/graphene is a single layer of graphite. Each carbon atom is bonded to three other carbon atoms in the layer.


b) Explain why graphene and fullerene are able to conduct electricity.

Answer: They both contain delocalised electrons.


c) What structural feature of magnesium fluoride makes it suitable for delivering drugs to specific parts of the body?

Answer: Fullerenes have hollow parts at the centre of the molecule that can be used as a cage/carry the drug molecule.


d) What structural feature of fullerenes makes them suitable for use as lubricants?

Answer: Fullerenes have roughly spherical shapes so they can roll past each other.


e) Carbon nanotubes have high tensile strength, which means that they are very strong when pulled or stretched. Explain why this is. Write about structure and bonding in your answer.

Answer: Carbon nanotubes are tubes of carbon atoms bonded together by strong covalent bonds. The strength of these bonds means it is hard to pull the carbon atoms apart, so the nanotube has a high tensile strength.


f) Diamond is a hard material that does not conduct electricity. Graphite is a soft material that does conduct electricity. Explain the differences in the properties of these two substances. Write about structure and bonding in your answer.

Answer: Diamond has a giant covalent structure in which each carbon atom is bonded to four other carbon atoms by covalent bonds. These bonds are very strong, (holding the atoms rigidly in place) so diamond is a hard substance. Diamond does not contain any delocalised electrons (as all the electrons are used in bonding) so it does not conduct electricity. Graphite has a giant covalent structure in which each carbon atom is bonded to only three other carbon atoms in flat layers. The layers themselves are not strongly bonded together and can slide over each other, making graphite soft. Graphite does contain delocalised electrons (as each carbon atom has one unbonded electron) so it does conduct electricity.