Why is dioxygen a gas but sulphur a solid?

Explanation

Oxygen forms `ppi-ppi` multiple bonds due to its small size and high electronegativity. As a result, oxygen exists as a diatomic molecule. These molecules are held together by weak van der Waals forces of attraction which can be overcome by collisions of the molecules at room temperature. Therefore `O_(2)` is a gas at room temperature. On the other hand, sulphur does not form `ppi-ppi` multiple bonds because of its bigger size and lower electronegativity, and forms only S - S single bonds. Sulphur has a stronger S- S than O - O single bonds. Consequently sulphur forms octaatomic (Sa) molecules having eight-membered puckered ring structure. Due to its big size, the interatomic forces of attraction of `S_(8)` molecules are very strong, which cannot be overcome by collisions of molecules at room temperature. Hence, sulphur is a solid at room temperature.