Technetium is a chemical element with the symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive, none of which is stable other than the fully ionized state of 97Tc. Nearly all available technetium is produced as a synthetic element. Naturally happening technetium is an unplanned quick fission product in uranium ore and thorium ore, the most common source, or the product of neutron take and hold to prevent release in molybdenum ores. The silvery gray, transparent change metamorphising metal lies between manganese and rhenium in group 7 of the list of all elements, and its chemical properties are halfway between those of both beside elements. The most common naturally happening isotope is 99Tc, in traces only.
Many of technetium’s properties had been (described a possible future event) by Dmitri Mendeleev before it was discovered. Mendeleev noted a gap in his list of all elements and gave the undiscovered element the temporary name ekamanganese (Em). In 1937, technetium (specifically the technetium-97 isotope) became the first mostly (not made by nature/fake) element to be produced, because of this its name (from the Greek ÏÎµÏÎ½Î·ÏÏÏ, meaning “Craft, Art or (not made by nature/fake)”, + -ium).
One short-lived (ray of invisible energy)-sending out nuclear isomer, technetium-99m, is used in nuclear medicine for a wide variety of tests, such as bone cancer (identifications of diseases or problems, or their causes). The ground state of the nuclide technetium-99 is used as a gamma-ray-free source of beta particles. Long-lived technetium isotopes produced commercially are (things produced along with something else) of the fission of uranium-235 in nuclear reactors and are (pulled out or taken from something else) from nuclear fuel rods. Because no isotope of technetium has a half-life longer than 4.21 million years (technetium-97), the 1952 detection of technetium in red giants helped to prove that stars can produce heavier elements.
From the 1860s through 1871, early forms of the list of all elements proposed by Dmitri Mendeleev contained a gap between molybdenum (element 42) and ruthenium (element 44). In 1871, Mendeleev (described a possible future event) this missing element would occupy the empty place below manganese and have almost the same chemical properties. Mendeleev gave it the temporary name ekamanganese (from eka-, the Withoutkrit word for one) because the (described a possible future event) element was one place down from the known element manganese.
The discovery of element 43 was finally confirmed in a 1937 experiment at the University of Palermo in Sicily by Carlo Perrier and Emilio Segre. In mid-1936, Segre visited the United States, first Columbia University in New York and then the Lawrence Berkeley National Laboratory in California. He convinced cyclotron inventor Ernest Lawrence to let him take back some thrown-out cyclotron parts that had become radioactive. Lawrence mailed him a molybdenum foil that had been part of the (object that pushes aside the flow of something) in the cyclotron.
Segre (joined the military) his fellow worker Perrier to attempt to prove, through (serving to compare two or more things) chemistry, that the molybdenum activity was in fact from an element with the atomic number 43. In 1937, th
ey succeeded in (separating far from others) the isotopes technetium-95m and technetium-97. University of Palermo (people in charge of something) wanted them to name their discovery “panormium”, after the Latin name for Palermo, Panormus. In 1947 element 43 was named after the Greek word ÏÎµÏÎ½Î·ÏÏÏ, meaning “(not made by nature/fake)”, since it was the first element to be (not in a natural way/in a fake way) produced. Segre returned to Berkeley and met Glenn T. Seaborg. They (separated far from others) the metastable isotope technetium-99m, which is now used in some ten million medical disease-identifying procedures every year.
In 1952, the star expert-related Paul W. Merrill in California detected the (related to ghosts or the colors of the rainbow) signature of technetium (specifically wavelengths of 403.1 nm, 423.8 nm, 426.2 nm, and 429.7 nm) in light from S-type red giants. The stars were near the end of their lives but were rich in the short-lived element, which pointed to/showed that it was being produced in the stars by nuclear reactions. That (event(s) or object(s) that prove something) helped (or increased) the educated guess that heavier elements are the product of (the act of creating atoms) in stars. More (not very long ago), such (instances of watching, noticing, or making statements) gave/given (event(s) or object(s) that prove something) that elements are formed by neutron take and hold (to prevent release) in the s-process.
Since that discovery, there have been many searches in (on land) materials for natural sources of technetium. In 1962, technetium-99 was (far apart from others) and identified in pitchblende from the Belgian Congo in very small amounts (about 0.2 ng/kg), where it starts as an unplanned (and sudden) fission product of uranium-238. The Oklo natural nuclear fission reactor contains (event(s) or object(s) that prove something) that big amounts of technetium-99 were produced and have since (rotted/became ruined or worse) into ruthenium-99.
Technetium is a silvery-gray radioactive metal with an appearance almost the same as platinum, commonly received/got as a gray powder. The crystal structure of the bulk (completely/complete, with nothing else mixed in) metal is six-sided close-packed. The crystal structure of the nanodisperse (completely/complete, with nothing else mixed in) metal is cubic. Nanodisperse technetium does not have a split NMR spectrum, while six-sided bulk technetium has the Tc-99-NMR spectrum split in 9 satellites. Atomic technetium has (typical and expected) emission lines at wavelengths of 363.3 nm, 403.1 nm, 426.2 nm, 429.7 nm, and 485.3 nm.
The metal form is (a) little paramagnetic, meaning its magnetic dipoles match up/make even with external magnetic fields, but will assume random (directions of pointing) once the field is removed. Pure, metallic, single-crystal technetium becomes a type-II superconductor at temperatures below 7.46 K. Below this temperature, technetium has a very high magnetic penetration depth, greater than any other element except niobium.
Technetium happens naturally in the Earth’s crust in minute concentrations of about 0.003 parts per trillion. Technetium is so rare because the half-lives of 97Tc and 98Tc are only 4.2 million years. More than a thousand of such periods have passed since the (creation and construction/ group of objects) of the Earth, so the chance for the survival of even one atom of very old (from the beginning of time) technetium is effectively zero. However, small amounts exist as unplanned (and sudden) fission products in uranium ores. A kilogram of uranium contains a guessed (number) 1 nanogram (10a’9 g) equal to ten trillion atoms of technetium. Some red giant stars with the (related to ghosts or the colors of the rainbow) types S-, M-, and N contain a (related to ghosts or the colors of the rainbow) (mental concentration/picking up of a liquid) line pointing to/showing the presence of technetium. These red-giants are known informally as technetium stars.
Technetium-99m (“m” points to/shows that this is a metastable nuclear isomer) is used in radioactive isotope medical tests. For example, Technetium-99m is a radioactive tracer that (X-rays, MRIs, etc.) equipment tracks in the human body. It is well suited to the role because it gives off easily detectable 140 keV (rays of invisible energy), and its half-life is 6.01 hours (meaning that about 94% of it (rots/becomes ruined/gets worse) to technetium-99 in 24 hours). The chemistry of technetium allows it to be bound to a variety of (related to the chemicals in living things) compounds, each of which decides/figures out how it is (chemically processed and used up) and deposited in the body, and this single isotope can be used for a large number of medical tests (to get information). More than 50 common radiopharmaceuticals are based on technetium-99m for imaging and functional studies of the brain, heart muscle, thyroid, lungs, liver, gall bladder, (organs that create urine), skeleton, blood, and tumors.
The longer-lived isotope, technetium-95m with a half-life of 61 days, is used as a radioactive tracer to study the movement of technetium in (the health of the Earth/the surrounding conditions) and in plant and animal systems.