Carbon-12

Carbon-12

Carbon-12 is an isotope of carbon, denoted as ¹²
C

. It is the most abundant of the two stable isotopes of carbon, making up about 98.93% of the carbon found on Earth. The nucleus of a carbon-12 atom consists of 6 protons and 6 neutrons.

Properties

Carbon-12 has an atomic mass of exactly 12 amu by definition. This isotope is used as the standard from which atomic masses of all nuclides are measured, a decision made by the International Union of Pure and Applied Chemistry (IUPAC) in 1961.

Role in Science

Carbon-12 plays a crucial role in chemistry and physics. It is the basis for the mole, a fundamental unit in the International System of Units (SI) used to measure the amount of substance. One mole of carbon-12 atoms has a mass of exactly 12 grams.

Formation

Carbon-12 is formed in stars through the triple-alpha process, a set of nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon.

Applications

Carbon-12 is widely used in mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy due to its non-radioactive nature and its abundance. It is also used in carbon dating to determine the age of archaeological and geological samples.

Related Isotopes

Other isotopes of carbon include carbon-13 and carbon-14. Carbon-13 is a stable isotope used in isotopic labeling and NMR spectroscopy, while carbon-14 is a radioactive isotope used in radiocarbon dating.

See Also

• Isotope
• Carbon
• Atomic mass unit
• Mole (unit)
• Triple-alpha process
• Mass spectrometry
• Nuclear magnetic resonance
• Carbon-13
• Carbon-14