Question

Why is carbon considered tetravalent?

Answer 1

The term tetravalent refers to the ability to bond four bonds with other atoms. It has the ability to share its four electrons with other four atoms and take part in bonding to form four covalent bonds.

Complete step-by-step answer: So we are supposed to explain why the carbon atom is considered to be a tetravalent atom. Before explaining about tetravalency of C, we have to know some basic ideas on valency, how bonds are formed, and what type of bond is formed by carbon etc.
The Valency of an atom can be explained as the combining property of the element, especially we can say by considering H atoms, how many H atoms can be bound with them or can be displaced from them etc.
The atomic number of carbon is 6, hence it has 6 electrons and the shell electronic configuration of C is 2, 4 i.e. K shell 2 electrons are present and in L shell 4 electrons are present.
So there are four valence electrons in the outermost shell of C which can be used for the bonding with other atoms and form four sigma bonds or can form multiple bonds with other atoms like triple bonds with N or double bonds with oxygen etc.
Now we have to discuss how C can form four bonds with other atoms, how it can extend its valency to 4.
The electronic configuration of C in ground state is $1{{s}^{2}}2{{s}^{2}}2{{p}^{2}}$
The electronic configuration of C in excited state is $1{{s}^{2}}2{{s}^{1}}2{{p}^{3}}$
In the excited state there are four unpaired electrons available for bonding and hence the carbon is considered as a tetravalent atom, which extends its valency to four to bond with atoms.

Note: Carbon atoms have a property called catenation in carbon atoms that can form bonds between themselves i.e. a C-C sigma or multiple bonds can be formed. Because of this property, carbon atoms are considered as the backbone for organic compounds. Carbon shares its electrons with other atoms and forms strong covalent bonds.