Carbon (C)
Reactive nonmetal
Carbon is the backbone of life and of an entire branch of chemistry. Its atoms bond into chains, rings and networks, producing millions of compounds — plus pure forms as different as soft graphite and diamond, the hardest natural material.
Position on the periodic table
Atomic properties
| Atomic number | 6 |
|---|---|
| Atomic mass | 12.011 amu |
| Electron configuration | 1s2 2s2 2p2 |
| Noble gas shorthand | [He] 2s2 2p2 |
| Electrons per shell | 2, 4 |
| Valence electrons (outer shell) | 4 |
| Common oxidation states | +4, -4, +2 |
| Electronegativity (Pauling) | 2.55 |
| Covalent radius (approx.) | 76 pm |
| First ionization energy | 1087 kJ/mol |
| Electron affinity | 121.8 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | 1.821 g/cm³ |
| Melting point | Not available |
| Boiling point | Not available |
| Appearance | Not available |
| Radioactive | No |
| Origin | Occurs naturally |
Electron configuration of carbon
Carbon's ground-state electron configuration is 1s2 2s2 2p2, usually shortened to [He] 2s2 2p2. Its electrons occupy 2 shells (2, 4), placing it in period 2 of the p-block. The 4 outer-shell electrons drive its bonding behaviour. Explore it interactively in the electron configuration calculator.
Uses of carbon
- Steelmaking (carbon strengthens iron)
- Fuels: coal, oil, natural gas
- Carbon fibre for bikes, cars and aircraft
- Activated charcoal filters
- Graphite electrodes and pencil cores
Biological role: The central element of life — every protein, sugar, fat and DNA molecule is built on carbon skeletons.
Occurrence: Found free as graphite and diamond and combined in carbonates, CO₂ and all living matter.
Common compounds of carbon
CO2
Carbon dioxide
CH4
Methane
C6H12O6
Glucose
CaCO3
Calcium carbonate
History and discovery
Discovered: Known since ancient times — Ancient Egypt. Name origin: From Latin carbo, meaning charcoal.
Known since prehistory as charcoal and soot. Antoine Lavoisier showed in the 1770s that diamond and charcoal are the same element.
Safety notes
Elemental carbon is harmless, but carbon monoxide (CO) from incomplete burning is a dangerous invisible gas.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Carbon
1. What is the chemical symbol of Carbon?
2. What is the atomic number of Carbon?
3. Which category does Carbon belong to?
4. What is the state of Carbon at room temperature?
5. Which period of the periodic table is Carbon in?
Carbon FAQs
What is the atomic number of carbon?
Carbon's atomic number is 6 — every carbon atom has 6 protons in its nucleus.
What is the symbol for carbon?
C. From Latin carbo, meaning charcoal.
Is carbon a metal, nonmetal, or metalloid?
Carbon is classified as a reactive nonmetal.
What state is carbon at room temperature?
At about 25 °C, carbon is a solid.
How many valence electrons does carbon have?
Carbon has 4 electrons in its outer shell (shell pattern: 2, 4).
What is carbon used for?
Key uses include: steelmaking (carbon strengthens iron); fuels: coal, oil, natural gas; carbon fibre for bikes, cars and aircraft.
Related elements
Keep working with this element
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