Examples of Isotopes and Their Uses
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Chlorine(Cl) has isotopes with mass numbers ranging from 32 g molâˆ’1 to 40 g molâˆ’1. There are two principal stable isotopes, 35Cl (75.76%) and 37Cl (24.24%), found in the relative proportions of 3:1 respectively, giving chlorine atoms in bulk an apparent atomic weight of 35.5.
Standard atomic mass: 35.453(2) u
NO amounts of radioactive36.0Cl exist in the environment, in a ratio of about 7x10âˆ’13 to 1 with stable isotopes. 36Cl is produced in the atmosphere by spallation of 36Ar by interactions with cosmic rayprotons. In the subsurface environment, 36Cl is generated primarily as a result of neutron capture by 35Cl or muon capture by 40Ca. 36Cl decays to 36S and to 36Ar, with a combined half-life of 308,000 years. The half-life of this hydrophilic nonreactive isotope makes it suitable for geologic dating in the range of 60,000 to 1 million years. Additionally, large amounts of 36Cl were produced by irradiation of seawater during atmospheric detonations of nuclear weapons between 1952 and 1958. The residence time of 36Cl in the atmosphere is about 1 week. Thus, as an event marker of 1950s water in soil and ground water, 36Cl is also useful for dating waters less than 50 years before the present. 36Cl has seen use in other areas of the geological sciences, forecasts, and elements.
A radionuclide is an atom with an unstable nucleus, which is a nucleus characterized by excess energy which is available to be imparted either to a newly-created radiation particle within the nucleus, or else to an atomic electron. The radionuclide, in this process, undergoes radioactive decay, and emits a gamma ray(s) and/or subatomic particles. These particles constitute ionizing radiation. Radionuclides may occur naturally, but can also be artificially produced.
The number of radionuclides is uncertain because the number of very short-lived radionuclides that have yet to be characterized is extremely large and potentially unquantifiable. Even the number of long-lived radionuclides is uncertain (to a smaller degree), because many "stable" nuclides are calculated to have half lives so long that their decay has not been experimentally measured. The nuclide list contain 90 nuclides that are theoretically stable, and 255 total stable nuclides that have not been observed to decay. In addition, there exist about 650 radionuclides that have been experimentally observed to decay, with half lives longer than 60 minutes (see list of nuclides for this list). Of these, about 339 are known from nature (they have been observed on Earth, and not as a consequence of man-made activities).
Including artificially produced nuclides, more than 3300 nuclides are known (including ~3000 radionuclides), including many more (> ~2400) that have decay half lives shorter than 60 minutes. This list expands as new radionuclides with very short half lives are characterized.
Radionuclides are often referred to by chemists and physicists, as radioactive isotopes or radioisotopes. Radioisotopes with suitable half lives play an important part in a number of constructive technologies (for example, nuclear medicine). However, radionuclides can also present both real and perceived dangers to health.
Naturally occurring radionuclides fall into three categories: primordial radionuclides, secondary radionuclides and cosmogenic radionuclides. Primordial radionuclides originate mainly from the interiors of stars and, like uranium and thorium, are still present because their half-lives are so long that they have not yet completely decayed. Secondary radionuclides are radiogenic isotopes derived from the decay of primordial radionuclides. They have shorter half-lives than primordial radionuclides. Cosmogenic isotopes, such as carbon-14, are present because they are continually being formed in the atmosphere due to cosmic rays.
Artificially produced radionuclides can be produced by nuclear reactors, particle accelerators or by radionuclide generators:
- Radioisotopes produced with nuclear reactors exploit the high flux of neutrons present. The neutrons activate elements placed within the reactor. A typical product from a nuclear reactor is thallium-201 and iridium-192. The elements that have a large propensity to take up the neutrons in the reactor are said to have a high neutron cross-section.
- Particle accelerators such as cyclotrons accelerate particles to bombard a target to produce radionuclides. Cyclotrons accelerate protons at a target to produce positron emitting radioisotopes e.g. fluorine-18.
- Radionuclide generators contain a parent isotope that decays to produce a radioisotope. The parent is usually produced in a nuclear reactor. A typical example is the technetium-99mgenerator used in nuclear medicine. The parent produced in the reactor is molybdenum-99.
- Radionuclides are produced as an unavoidable side effect of nuclear and thermonuclear explosions.
Trace radionuclides are those that occur in tiny amounts in nature either due to inherent rarity, or to half-lives that are significantly shorter than the age of the Earth. Synthetic isotopes are inherently not naturally occurring on Earth, but can be created by nuclear reactions.
Radionuclides are used in two major ways: for their chemical properties and as sources of radiation. Radionuclides of familiar elements such as carbon can serve as tracers because they are chemically very similar to the non-radioactive nuclides, so most chemical, biological, and ecological processes treat them in a near identical way. One can then examine the result with a radiation detector, such as a geiger counter, to determine where the provided atoms ended up. For example, one might culture plants in an environment in which the carbon dioxide contained radioactive carbon; then the parts of the plant that had laid down atmospheric carbon would be radioactive.
In nuclear medicine, radioisotopes are used for diagnosis, treatment, and research. Radioactive chemical tracers emitting gamma rays or positrons can provide diagnostic information about a person's internal anatomy and the functioning of specific organs. This is used in some forms of tomography: single photon emission computed tomography and positron emission tomography scanning.
radioactive isotope or radioisotope, natural or artificially created isotope of a chemical element having an unstable nucleus that decays, emitting alpha, beta, or gamma rays until stability is reached. The stable end product is a nonradioactive isotope of another element, i.e., radium-226 decays finally to lead-206. Very careful measurements show that many materials contain traces of radioactive isotopes. For a time it was thought that these materials were all members of the actinide series ; however, exacting radiochemical research has demonstrated that certain of the light elements also have naturally occurring isotopes that are radioactive. Since minute traces of radioactive isotopes can be sensitively detected by means of the Geiger counter and other methods, they have various uses in medical therapy, diagnosis, and research. In therapy, they are used to kill or inhibit specific malfunctioning cells. Radioactive phosphorus is used to treat abnormal cell proliferation, e.g., polycythemia (increase in red cells) and leukemia (increase in white cells). Radioactive iodine can be used in the diagnosis of thyroid function and in the treatment of hyperthyroidism. Since the iodine taken into the body concentrates in the thyroid gland, the radioaction can be confined to that organ. In research, radioactive isotopes as tracer agents make it possible to follow the action and reaction of organic and inorganic substances within the body, many of which could not be studied by any other means. They also help to ascertain the effects of radiation on the human organism (see radiation sickness ). In industry, radioactive isotopes are used for a number of purposes, including measuring the thickness of metal or plastic sheets by the amount of radiation they can stop, testing for corrosion or wear, and monitoring various processes.
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Answers:Carbon-14: Archaeological dating Americium-241: Smoke detectors Cobalt-60: Food Irradiation Phosphorus-32: Biology study
Answers:An isotope is one of several atomic forms of an element, each containing a different number of neutrons and thus differing in atomic mass. For your example, hydrogen contains 1 proton inside the nucleus, and of course, 1 electron that orbits the nucleus. As in the definition, an isotope of hydrogen differs only in the number of neutrons it contains. Thus, an isotope of hydrogen can contain 1 neutron, 2 neutrons, etc. There are limits to containing a reasonable amount of extra neutrons, but that is another matter. Anyway, with hydrogen essentially containing an extra neutron, its atomic mass is altered about 1 amu. (Neutrons and protons way about 1 atomic mass unit (amu) each while electrons way almost nothing.) This makes the hydrogen atom considerably heavier. An addition to atomic mass, neutrons affect the atom's stability and nuclear properties. With too few or too much neutrons, nuclear properties become more severe, making the atom unstable and exposed to decay. This is due to the neutrons neutral charge opposed to the protons positive charge; both are located next to each other inside the nucleus. The separation of protons by neutrons affects the energy between adjacent protons. Hope this helps!!
Answers:We have isotopes of cobalt(Co) used in the treatment of cancer.The isotopes of iodine are used to treat goitre. In matters of industry, Isotopes of hydrogen( protium -H1, deutirium H2 and tritium H3 ) are used to make hydrogen bombs by nuclear fusion method. Isotopes of uranium(Ur235 and Ur238 ) are used to make nuclear reactors. Isotopes of oxygen( O16 and O18 ) are also used in the industry
Answers:There are over 200 isotopes. Two of the most commonly used isotopes are C13 which is used for Carbon Dating and Deuterium which is H2. It is used as a tracer in environmental systems and is a result of nuclear bomb testing.