Which of the following is

Solution

The elements which exist as single atom are called monoatomic elements. The elements which exist in atomic pairs bonded to each other are called diatomic elements. The elements which exist as groups of more than two atoms are called polyatomic elements. Chlorine (Cl2), Nitrogen (N2) and Hydrogen (H2) are diatomic gases. But sulphur exists as S8 and hence it is polyatomic. Selenium (Se8), Ozone (O3) and Phosphorous (P4) some other polyatomic elements.