Why is dioxygen gas but sulphur a solid?

Why oxygen is gas while sulphur is a solid at room temparture ?

Both diamond and rhombic sulphur are covalent solids but the latter has very low melting point than the former. Explain why?

Write a balanced chemical equation for each of the following reactions and also classify them . Hydrogen sulphide gas reacts with oxygen gas to form solids sulphur and liquid water .

Why does concentrated sulphuric acid has high boiling point?

Explain why perchloric acid is a strong acid than sulphuric acid.