Question

Why diamond is a hard and the graphite is very soft.

Answer 1

• Carbon alone forms the familiar substances graphite and diamond. Both graphite and diamond are made only of carbon atoms.
• Graphite is very soft and slippery while Diamond is the hardest substance.
• While there are strong covalent bonds between carbon atoms in each layer, there are only weak forces between layers. This allows layers of carbon to slide over each other in graphite.
• On the other hand, in diamonds, each carbon atom is the same distance from each of its neighboring carbon atoms. they are bonded by strong covalent bonds
• Diamond is hard because it has four carbon atoms which form a strong covalent bond in tetrahedral structure whereas graphite is arranged in layer form through weak wander walls force hence is slippery in nature.
• For example:

1. The slippery nature of graphite is attributed to the pencil lead.

2. The hardness of a diamond is used to drill, grind or cut materials.

3. Graphite is a good conductor because of the free electrons present in it.