Fast facts. Name: sulfur Symbol: S Atomic number: 16 Atomic weight: 32.065 (5) g r. Group number: 16 Group name: Chalcogen Period number: 3 Block: p-block . spelling. The spelling of sulphur is \"sulfur\" in the USA and now that IUPAC has decided it has jurisdiction over the British English language (as distinct from American English) as well as nomenclature, so people in the UK are expected to use the f word. .