Answer: Option (a) is the correct answer.
Explanation:
When there is sharing of electrons between two atoms then it results in the formation of a covalent bond.
For example, carbon has atomic number 6 and its electronic distribution is 2, 4. Whereas oxygen atom has atomic number 8 and its electronic distribution is 2, 6.
Therefore, both carbon and oxygen atoms share their valence electrons in order to complete their octet and results into the formation of a coavlent compound [tex]CO_{2}[/tex].
On the other hand, an ionic bond is formed by transfer of electrons between the combining atoms.
Therefore, we can conclude that a covalent bond forms when two atoms share one or more pairs of electrons.
