CBSE Class 9 Answered

Elements exhibit allotropy as there are varous ways in which the atoms can be linked together into molecules and also different ways in which the molecules can be arranged to make larger structures.

In the case of carbon, the atoms form either giant macromolecular structures (diamond and graphite) in which all of the atoms in the bulk structure are joined together by covalent bonds making giant molecules, or smaller molecules (buckminster fullerene) in which there are only discrete molecules made up of 60 carbons in a structure resembling a football (hence the nickname 'bucky balls')