Isotope
hideIsotopes (Greek isos = "equal", tópos = "site, place") are any of the different types of atoms (nuclides) of the same chemical element, each having a different atomic mass (mass number). Isotopes of an element have nuclei with the same number of protons (the same atomic number) but different numbers of neutrons. Therefore, isotopes of the same element have different mass numbers (number of nucleons).
A nuclide is any particular atomic nucleus with a specific atomic number Z and mass number A; it is equivalently an atomic nucleus with a specific number of protons and neutrons. Collectively, all the isotopes of all the elements form the set of nuclides. The distinction between the terms isotope and nuclide has somewhat blurred, and they are often used interchangeably. If they are to be distinguished in use, isotope is better used in its original sense, when referring to several different nuclides of the same chemical element. Nuclide is a later and more generic term, and is used when referencing to only one type of nucleus, and may also be used to refer to several types of nuclei of different elements. For example, it is better to say that an element such as fluorine consists of one stable nuclide rather than that it has one stable isotope, because the latter word is usually reserved to refer to more than one nuclide. On the other hand, carbon can be correctly said to have two stable isotopes, and fluorine to have several radioactive isotopes.
Isotopes and nuclides are specified by the name of the particular element, implicitly giving the atomic number, followed by a hyphen and the mass number (e.g. helium-3, carbon-12, carbon-13, iodine-131 and uranium-238). In symbolic form, the number of nucleons is denoted as a superscripted prefix to the chemical symbol (e.g. 3He, 12C, 13C, 131I and 238U).
About 339 nuclides occur naturally on Earth, of which 256 (about 75%) are stable (or, to be careful, have never been observed to decay; this note is necessary because many "stable" isotopes are predicted to be radioactive with very long half-lives). Counting the radioactive nuclides not found in nature that have been created artificially, more than 3100 nuclides are currently known.
For more information about Isotope, read the full article at
Wikipedia.
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News tagged with isotopes
Proton's party pals may alter its internal structure
Nov 18, 2009 |
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A recent experiment at the DOE's Thomas Jefferson National Accelerator Facility has found that a proton's nearest neighbors in the nucleus of the atom may modify the proton's internal structure.
Earth's early ocean cooled more than a billion years earlier than thought (w/ Video)
Space & Earth / Earth Sciences
Nov 11, 2009 |
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(PhysOrg.com) -- The scalding-hot sea that supposedly covered the early Earth may in fact never have existed, according to a new study by Stanford University researchers who analyzed isotope ratios in 3.4 ...
Atomic Particles Help Solve Planetary Puzzle
Space & Earth / Earth Sciences
Nov 10, 2009 |
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(PhysOrg.com) -- A University of Arkansas professor and his colleagues have shown that the Earth's mantle contains the same isotopic signatures from magnesium as meteorites do, suggesting that the planet formed ...
Are the Alps growing or shrinking?
Space & Earth / Earth Sciences
Nov 05, 2009 |
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The Alps are growing just as quickly in height, as they are shrinking. This paradoxical result could be proven by a group of German and Swiss geoscientists. Due to glaciers and rivers about exactly the same amount of material ...
High-performance plasmas may make reliable, efficient fusion power a reality
Nov 02, 2009 |
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In the quest to produce nuclear fusion energy, researchers from the DIII-D National Fusion Facility have recently confirmed long-standing theoretical predictions that performance, efficiency and reliability ...
Snail fossils suggest semiarid eastern Canary Islands were wetter 50,000 years ago
Space & Earth / Earth Sciences
Oct 27, 2009 |
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Fossil land snail shells found in ancient soils on the subtropical eastern Canary Islands show that the Spanish archipelago off the northwest coast of Africa has become progressively drier over the past 50,000 years.
The greenhouse gas that saved the world
Space & Earth / Earth Sciences
Aug 18, 2009 |
3.6 / 5 (9) |
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When Planet Earth was just cooling down from its fiery creation, the sun was faint and young. So faint that it should not have been able to keep the oceans of earth from freezing. But fortunately for the creation of life, ...
Rebooting of Canadian medical isotope reactor delayed
Aug 13, 2009 |
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A Canadian reactor that produced one-third of the world's supply of medical isotopes before it closed in May for repairs will remain offline at least until early 2010, nuclear authorities said Thursday.
New laser technique may help find supernova
Aug 11, 2009 |
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One single atom of a certain isotope of hafnium found on Earth would prove that a supernova once exploded near our solar system. The problem is how to find such an atom - among billions of others. Researchers at the University ...
Diet, population size and the spread of modern humans into Europe
Other Sciences / Archaeology & Fossils
Aug 11, 2009 |
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Stable isotope data published this week in the Proceedings of the National Academy of Sciences by Erik Trinkaus, professor of anthropology at Washington University in St. Louis, and Michael Richards of the University of Bri ...
Mars breakthrough: Scientists uncover red planet's hot and steamy secrets
Space & Earth / Space Exploration
Jul 21, 2009 |
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(PhysOrg.com) -- An analysis of Martian meteorites has led scientists to believe that Mars was molten for up to 100 million years after it formed, thwarting the evolution of early life on the planet.
New isotope cluster could lead to better understanding of atmospheric carbon dioxide
Space & Earth / Earth Sciences
Jul 14, 2009 |
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(PhysOrg.com) -- A team of researchers has discovered an unexpected concentration of a certain isotopic molecule in parts of the stratosphere that could have implications for understanding the carbon cycle ...
Methane-eating microbes can use iron and manganese oxides to 'breathe'
Space & Earth / Earth Sciences
Jul 09, 2009 |
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Iron and manganese compounds, in addition to sulfate, may play an important role in converting methane to carbon dioxide and eventually carbonates in the Earth's oceans, according to a team of researchers ...
Looking for signs of early life
Space & Earth / Earth Sciences
Jul 08, 2009 |
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(PhysOrg.com) -- Deciphering the very early history of life on Earth is difficult. In the darkest recesses of the first billion years there are no 'body' fossils - no physical remains. Instead, scientists ...
A top supplier of medical isotopes closed through 2009
Jul 08, 2009 |
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An aging Canadian nuclear reactor responsible for production of one-third of the isotopes used in medical radiation treatment around the world will be out of service through at least the end of 2009, authorities said Wednesday.
