Final answer:
Carbon is unique among the other elements as its atoms can form stable covalent bonds with each other and with atoms of other elements, resulting in a wide range of molecules. Diamond and graphite are two common forms of carbon with distinct properties due to the different arrangements of carbon atoms.
Step-by-step explanation:
Carbon is unique among the other elements in that its atoms can form stable covalent bonds with each other and with atoms of other elements in a multitude of variations. The resulting molecules can contain from one to millions of carbon atoms. Carbon is an essential element in our world and forms a huge variety of substances that we use on a daily basis. For example, diamond and graphite are two common allotropes of carbon with very different properties, such as hardness and softness, due to the different arrangements of carbon atoms.