Allotropes of carbon

Question 1

Diamond is hard and has a high melting and boiling point.

Answer 1

Each carbon atom is covalently bonded to 4 other carbon atoms, which in turn are bonded to 4 more carbon atoms. This forms a 3-D structure. It is difficult to break these covalent bonds.

Question 2

Diamond does not conduct electricity.

Answer 2

In the diamond structure, all the outer electrons of the carbon atoms are used for bonding. Thus, there are no free electrons that move through the structure to conduct electricity.

Question 3

Graphite has a high melting and boiling point.

Answer 3

Each carbon atom is covalently bonded to 3 other carbon atoms, which in turn are bonded to 3 more carbon atoms. This forms a continuous layer of hexagons. It is difficult to break these strong covalent bonds.

Question 4

Graphite is soft and slippery.

Answer 4

The layers of carbon atoms are held loosely by weak intermolecular forces of attraction. These layers of carbon atoms can slide over each other when a force is applied.

Question 5

Graphite conducts electricity.

Answer 5

Each carbon atom has 1 outer electron that is not used to form covalent bonds. these electrons can move freely from 1 carbon atom to the next. They are said to be delocalised. These free-moving electrons allow graphite to conduct electricity.