Question

Why does carbon form compounds mainly by covalent bonds. Explain in brief two main reasons for carbon forming a large number of compounds. Why does carbon form strong bonds with most other elements?

Answer 1

The carbon is a tetravalent compound which means it has only four electrons in the outermost orbital which it can share with other elements to form a bond. The carbon cannot form ions.

Complete step by step answer: The atomic number of carbon is 6. The electronic configuration of carbon is $[He]2{s^2}2{p^2}$. The carbon contains 4 valence electrons in the outermost shell so it can either gain 4 electrons or lose 4 electrons to attain a stable electronic configuration but due to high energy requirements the carbon cannot accept or gain electrons. Therefore, it shares its four electrons with the neighbouring atoms to form a covalent bond. Thus, carbon possesses tetravalency.
The two main reasons for the carbon to form a large number of compounds are shown below.
(1) Catenation: Carbon can bond with other carbon atoms through sigma bond or pi bond to form a long chain of hydrocarbons. This unique property of carbon is known as catenation.
(2) Tetravalency: As carbon has four valence electrons in the outermost orbital. It can share its four electrons to form bonds with other four carbon atoms or any other element like hydrogen, oxygen, halogens.
As the size of the carbon atom is very small. Thus, the nucleus holds the shared pair of electrons very strongly. Therefore, it forms strong bonds with other elements.

Note: Catenation can be seen in other elements apart from carbon like silicon, sulfur and boron. In the periodic table, the catenation property is shown by element of group 4. As we move down in the group, the catenation property decreases.