Question

Explain the following : (a) tetravalency (b) catenation. [4 MARKS]

Answer 1

Each Part: 2 Marks

(a) Tetravalency: Atomic number of carbon is 6. Its electronic configuration is 2, 4. Therefore, it has four electrons in its valence shell. Carbon atom can neither lose nor gain electrons to complete its octet (not possible from energy point of view). Therefore, carbon atom completes its octet by sharing four electrons with other atoms i.e., it can form four covalent bonds. This is called tetracovalency.
For example :
Methane, $C{H}_4$



(b) Catenation: The property by virtue of which a large number of atoms of the same element get linked together through covalent bonds, forming straight or branched chains and rings of different sizes, is called catenation. Carbon shows catenation to the maximum extent due to strong carbon-carbon bonds and its tetracovalency. In this process of catenation, carbon atoms form straight, branched and cyclic chains of atoms and can involve in single, double or triple covalent bonds.