Related questions What periodic table elements are radioactive? How can the periodic table be used to predict the properties of the elements? How can elements have different isotopes? How can elements be broken down? How can elements properties be predicted? This is a preview of subscription content, log in to check access. Avery SV Metal toxicity in yeast and the role of oxidative stress. Beveridge T Bacterial S-layers. Darling D ed Encyclopedia of science online Google Scholar.
Grossmann G, Neu M, Pantos E et al X-ray solution scattering reveals conformational changes upon iron uptake in lactoferrins, serum and ovaltransferrins. Michon J, Frelon S, Garnier C, Coppin F Determinations of uranium VI binding properties with some metalloproteins transferring, albumin, metallothionein and ferritin by fluorescence quenching.
Seeger PA et al Neutron resonance scattering shows specific binding of plutonium to the calcium binding sites of the protein calmouldin and yields precise distance information. Follow us on Facebook Follow us on LinkedIn. Main Content. Sub-navigation Campaign Recommended viewing Want to learn more about one of science's heroes from history, Henry Moseley? Actinides and Lanthanides The lanthanides and the actinides are usually shown as two additional rows below the main body of the periodic table.
Featured Element: Uranium All isotopes of uranium are unstable, with half-lives varying 4. Nowadays, Uranium is mined in 20 countries, with over half coming from Canada, Kazakhstan, Australia, Niger, Russia and Namibia Uranium was discovered in pitchblende in , by Martin Heinrich Klaproth, and named after the recently discovered planet Uranus. Diamond's expanding role in radioactive waste research The use of nuclear energy to produce electricity has avoided the release of an estimated 56 gigatonnes of carbon dioxide since Hematite can lock the door on uranium contamination X-ray spectroscopy techniques at Diamond have given scientists a new insight into the behaviour of uranium during deep disposal of radioactive waste.
Looking inside the radioactive box At sites such as Sellafield, substantial quantities of uranium are stored in a range of environments at different stages of corrosion. During corrosion, metal oxides and hydrogen gas are produced. As hydrogen accumulates, the corrosion of uranium may switch to produce uranium hydride UH 3 instead.
This pyrophoric compound reacts vigorously with oxygen to make UO 2 , and as such is thought to exist only fleetingly. Researchers wanted to investigate the risk posed by an accumulation of pyrophoric uranium hydride. For these experiments, UH3 was stored underwater after being artificially formed on a uranium rod and encased in the grout used at nuclear waste facilities.
The sample underwent periodic testing at 0, 3, and 10 months on the Joint Engineering, Environmental, and Processing beamline I Because thorium is a weak alpha emitter, it is relatively safe to use in some commercial applications. Thorium is used as an alloying agent for some metals, such as magnesium, to improve their high-temperature strength.
It is also used in elecronic photosensors to measure ultraviolet light. Thorium IV oxide, ThO 2 , used to be used in mantles in portable gas lights. It is an ingredient in some high-quality lenses, since it forms glasses with a high refractive index and low dispersion.
It is also used as a catalyst for the conversion of ammonia to nitric acid, in petroleum cracking, and in the production of sulfuric acid. Thorium can be converted into thorium by bombardment with neutrons, thereupon decaying into protactinium and then into uranium Uranium undergoes nuclear fission in a chain reaction, and this cycle has potential to be used in nuclear fusion plants.
Because thorium is more abundant than uranium, this may hold some promise in later generations of nuclear power plants. Protactinium is a silvery-white, radioactive metal. Its name is derived from the Greek word proto and actinium , meaning "parent of actinium," because it undergoes radioactive decay to produce actinium.
It is found in the Earth's crust in trace amounts, and is among the ten least abundant elements. It is found in uranium ores such as pitchblende, at very low concentrations. Protactinium is extremely radioactive. It oxidizes slowly in air. There are two naturally occurring isotopes of protactinium: protactinium, with a a half-life of 6 hours and 42 minutes, and protactinium, with a half-life of 32, years.
Because it is highly radioactive and toxic, there are no commercial applications for protactinium. Uranium is a lustrous, silvery-white, hard, dense, malleable, radioactive metal.
It is named for the planet Uranus, which had been discovered a few years before the discovery of the element in The planet Uranus had in turn been named for the Greek god of the sky. It is found in the Earth's crust at a concentration of 2 ppm, making it the 48th most abundant element. Lignite coal and monazite ore also contains trace amounts of uranium. Uranium tarnishes in air to produce an oxide coating. One of the most important properties of uranium was not discovered until , when Henri Becquerel discovered that uranium is radioactive.
In one of the classic examples of "accidental" discovery in science, he placed a sample of uranium salts next to a photographic plate, intending to examine the phosphorescence of uranium when exposed to sunlight.
However, he discovered that the plates were exposed, even though the sample had remained in the dark, and realized that the uranium was spontaneously emitting a type of radiation that was not connected to any external stimulation. There are three major naturally occurring isotopes of uranium there are quite a few other isotopes, but their half-lives are relatively short, and they are not found in any significant amounts in natural sources.
The major isotope is uranium, which has an abundance of It emits alpha particles and gamma rays, and is non-fissionable, absorbing neutrons instead of splitting. Uranium, which has an abundance of 0. It also emits alpha particles and gamma rays, and is fissionable , splitting into lighter atoms when struck by a neutron.
Uranium, which has a half-life of , years, is found at very low concentrations, about 0. Uranium eventually decays into lead, and uranium into lead The radioactive decay of uranium isotopes contributes a great deal to the internal heat of the Earth. The relative amounts of uranium and lead in rocks can be used in radioactive dating techniques. When neutrons are fired at uranium, the extremely unstable uranium isotope is produced, which quickly splits into two smaller nuclei such as barium and krypton , releasing some of the nuclear binding energy and more neutrons.
This process is known as nuclear fission. These neutrons can collide with other uranium isotopes, causing them to split and release energy and even more neutrons in a chain reaction. Moderators such as beryllium, graphite, water, or heavy water D 2 O slow down the neutrons that are released in fission reactions, producing "thermal neutrons" that can be captured by uranium atoms, rather than simply bouncing off.
In "light water" reactors, the moderator is ordinary water — i. In "heavy water" reactors, the moderator is D 2 O — i.
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