What do chalk, sugar, soap, polythene, nylon and vinegar have in common?
The element carbon. Carbon is a non-metallic element and is denoted by the symbol C. It is found in both crystalline and amorphous (where the atoms of the substance are not arranged in a regular crystalline pattern) forms. The two most common forms of amorphous carbon are charcoal and coke. Common forms of crystalline carbon are diamond and graphite. The different structures of both diamond and graphite give them different properties, even though they are both compounds of carbon.
Diamonds is the hardest known substance because of the way its atoms are arranged. Four atoms surround each carbon atom. Industrial diamonds, which may be natural or man-made, are used for cutting, grinding and polishing. Glass is cut using diamonds. When a person buys a diamond, he examines its physical properties: the cut, the colour, its weight or carat, and its clarity.
In graphite, three atoms surround each carbon atom. The atoms are arranged in flat layers, due to which they can slide over each other. This property of graphite makes it a good lubricant. Graphite is a component of pencil lead. It is also a good conductor of heat and electricity and is therefore used in nuclear reactors.