CBSE Class 10 Answered

The electronic configuration of the carbon atom allows it to form a number of hybridized atomic orbitals. Carbon atoms in the elemental substances (e.g., diamond, graphite) bonds to each other covalently, by the sharing of electron pairs. The covalent bonds have directional properties. This in turn gives carbon the ability to adapt into various molecular and crystalline structures. The nature of these bonds underlies the varied chemical properties and physical properties of the carbon allotropes. 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. Diamond is the hardest substance known to man. They have different structures and properties and the reason for this lies in the way the carbon atoms form bonds with each other. 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 diamond each carbon atom is the same distance to each of its neighboring carbon atoms. In this rigid network atoms cannot move. This explains why diamonds are so hard and have such a high melting point.