Sulfur (S)
Reactive nonmetal
Sulfur is a bright yellow nonmetal known since ancient times as brimstone. It is mined and recovered from oil refining in enormous quantities, mostly to make sulfuric acid — the world's most-produced industrial chemical.
Position on the periodic table
Atomic properties
| Atomic number | 16 |
|---|---|
| Atomic mass | 32.06 amu |
| Electron configuration | 1s2 2s2 2p6 3s2 3p4 |
| Noble gas shorthand | [Ne] 3s2 3p4 |
| Electrons per shell | 2, 8, 6 |
| Valence electrons (outer shell) | 6 |
| Common oxidation states | -2, +4, +6 |
| Electronegativity (Pauling) | 2.58 |
| Covalent radius (approx.) | 105 pm |
| First ionization energy | 999.6 kJ/mol |
| Electron affinity | 200.4 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | 2.07 g/cm³ |
| Melting point | 115.21 °C (388.36 K) |
| Boiling point | 444.65 °C (717.8 K) |
| Appearance | lemon yellow sintered microcrystals |
| Radioactive | No |
| Origin | Occurs naturally |
Electron configuration of sulfur
Sulfur's ground-state electron configuration is 1s2 2s2 2p6 3s2 3p4, usually shortened to [Ne] 3s2 3p4. Its electrons occupy 3 shells (2, 8, 6), placing it in period 3 of the p-block. The 6 outer-shell electrons drive its bonding behaviour. Explore it interactively in the electron configuration calculator.
Uses of sulfur
- Sulfuric acid for fertilisers, batteries and industry
- Vulcanising rubber (making tyres durable)
- Fungicides and preserving dried fruit
- Gunpowder and matches
Biological role: Essential — two amino acids contain sulfur, and sulfur bridges give proteins (and hair) their shape.
Occurrence: Found free near volcanoes and in sulfide/sulfate minerals; recovered on a huge scale from natural gas and oil.
Common compounds of sulfur
H2SO4
Sulfuric acid
SO2
Sulfur dioxide
H2S
Hydrogen sulfide
FeS2
Pyrite (fool's gold)
History and discovery
Discovered: Known since ancient times — Ancient china. Name origin: From Latin sulpur/sulfur, an ancient name for brimstone.
Known for thousands of years; Lavoisier convinced chemists in 1777 that it was an element, not a compound.
Safety notes
Elemental sulfur is low-toxicity, but sulfur dioxide irritates lungs and sulfuric acid is highly corrosive.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Sulfur
1. What is the chemical symbol of Sulfur?
2. What is the atomic number of Sulfur?
3. Which category does Sulfur belong to?
4. What is the state of Sulfur at room temperature?
5. Which period of the periodic table is Sulfur in?
Sulfur FAQs
What is the atomic number of sulfur?
Sulfur's atomic number is 16 — every sulfur atom has 16 protons in its nucleus.
What is the symbol for sulfur?
S. From Latin sulpur/sulfur, an ancient name for brimstone.
Is sulfur a metal, nonmetal, or metalloid?
Sulfur is classified as a reactive nonmetal.
What state is sulfur at room temperature?
At about 25 °C, sulfur is a solid. It melts at 115.21 °C.
How many valence electrons does sulfur have?
Sulfur has 6 electrons in its outer shell (shell pattern: 2, 8, 6).
What is sulfur used for?
Key uses include: sulfuric acid for fertilisers, batteries and industry; vulcanising rubber (making tyres durable); fungicides and preserving dried fruit.
Related elements
Keep working with this element
Spotted an error? Report a correction · Data sources