State the terms:

(a) Substances whose atoms or molecules are arranged in a definite pattern.

(b) Different forms of an element found in the same physical state.

(c) The property by which atoms of an element link together to form long chain or ring compounds.

Name the following:

(a) The hardest naturally occurring substance.

(b) A greyish black non-metal that is a good conductor of electricity.

(c) The third crystalline form of carbon.

Why is diamond very hard?

What are fullerenes? Name the most common fullerene.