(i) What is meant by covalent bond?
(ii) Explain the covalent bonding in `H_(2), O_(2), N_(2).`

Explanation

(i) Mutual sharing of one or more pair of electrons between two combining atoms results in the formation of a chemical bond called a covalent bond.
(ii) two atoms share just one pair of electron, a single covalent bond is formed as in the case of hydrogen molecule
(iii) If two or three electron pairs are shared between the two combining atoms, then the covalent bond is called double bond and triple bond respectively, as in the case of `O_(2) and N_(2)` molecules respectively.