Question

Give a reason for carbon is tetravalent in nature.

Answer 1

The electronic configuration of carbon is:
1s² 2s² $$2\mathrm{p}{\phantom{A}}_{\text{x}}^1$$ $$2\mathrm{p}{\phantom{A}}_{\text{y}}^1$$
One electron from ‘2s’ orbital is promoted to the empty ‘2p’ orbital.
Thus, in an excited state, carbon has four half-filled orbitals.

C = 

1s	2s	2p
↑↓	↑	↑	↑	↑

Hence, carbon can form 4 bonds and is tetravalent in nature.