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| Technetium is not found on earth, but if you go to outer space you will find what it's worth. |
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For many many years there was an element missing in the periodic table between molybdenum(#42) and Ruthenium(44). Many early researchers were eager to be the first to discover and name the missing element; its location in the table suggested that it should be easier to find than other undiscovered elements. It was first guessed to have been found platinum ores in 1828. It was given the name polinium but it turned out to be impure iridium. Dimitri Mendeleev predicted technetium’s properties before it was discovered, thought it was chemically close to maganese and he gave it the name ekamaganese. The discovery of Technetium was finally discovered in Italy in 1937 by Emilio Segré and Carlo Perrier using a sample of material sent to them by scientists at the University of California at Berkeley.(Segre Emiolio on the left, and Carlo Perrier to the right.) |
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Technetium is used for imaging and functional studies of the brain,myocardium, thyroid, lungs, liver,bladder,kidneys,skeleton,tumors, and blood. Technetium can be injected into the blood stream to help doctors get images of the heart.
Immonuscintygraphy incorporates technetium into a monoclonal antibody,an immune system protein, capable of binding to cancer cells. A few hours after injection, medical equipment is used to detect the gamma rays released by the higher concentrations indicate where the tumor is. This technique is useful for hard-to-find cancers, such cancers that affect the intestine. When Technetium is combined with a tin compound it binds red blood cells and can be used to map circulatory system disorders. It is commonly used to detect gastrointestinal bleeding sites. A pyrophosphate ion with Technetium helps calcium deposits in damaged heart muscle, making it useful to help damage after a heart attack. |
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Reactivity/Decay
It is a gamma ray emitting isotope used in radioactive isotope medical tests, for example as a radioactive tracer that medical equipment can detect in the body. It is well suited to the role because it emits readily detectable gamma rays (these are about the same wavelength emitted by conventional X-ray diagnostic equipment), and its half-life for gamma emission is 6.01 hours (meaning that about fifteen sixteenths (93.7%) of it decays to 99Tc in 24 hours). The short half life of the isotope allows for scanning procedures which collect data rapidly, but keep total patient radiation exposure low. Technetium-99m decays to technetium (Tc-99, a less excited state of the same isotope) by rearrangement of nucleons its nucleus. Technetium-99 emits soft beta rays but no gamma rays. |
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characteristics
Technetium is a silvery-grey radioactive metal that looks similar to platinum. However, it is usually a grey powder. Its position of the periodic table is between rhenium and manganese and as predicted by the periodic law its properties are very similar those two elements. Technetium is unusual among the lighter elements and it has no stable isotopes. Only technetium and promethium have no stable isotopes, but are followed by elements which do.
Technetium is extremely rare on Earth. Technetium plays no natural biological role and is not normally found in the human body.
The metal form of technetium slowly tarnishes in moist air. Its oxidation numbers are TcO2 and Tc2O7. Technetium will burn in oxygen when in powder form. It dissolves in aqua regia, nitric acid, and concentrated sulfuric acid, but it is not soluble in hydrochloric acid. |
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isotopes
Technetium is one of the two elements in the first 82 that have no stable isotopes (it is the lowest-numbered element that is exclusively radioactive); the other element, Promethium has the most stable isotopes . Twenty-two other radioisotopes have been characterized with atomic masses.Technetium also has numerous meta states. Technetium only emits gamma rays, so it decays into Technetium.
For isotopes lighter than the most stable isotope,Technetium , the primary decay mode is electron capture, giving molybdenum. For the heavier isotopes, the primary mode is beta decay, giving ruthenium, with the exception that technetium can decay both by beta emission and electron capture. |
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| Atomic number |
43 |
| atomic weight |
98.91 |
| melting point |
3915 F |
| group number |
7 |
| period number |
5 |
| boiling point |
7709 F |
| Glossary |
Hydrochloric acid-a colorless or faintly yellow, corrosive, fuming liquid, HCl, used chiefly in chemical and industrial processes.
Molybdenum-an element to the left of Technetium
Beta decay-A neutron inside of the nucleus of an unstable atom changes into negatively charged beta particle and a proton.
Radioactivity-The ability of a substance to spontaneously emit radiation; a property of unstable isotopes.
Isotope-Atoms of the same element that have different numbers of neutrons
Tarnish-to dull the luster (of a metal) |
| Bibliography |
1) MIller, Ron. The elements, what you really want to know. Minneapolis, MInnesota: Twenty-First Century Books, 2006.
2) Physical Science. Boston,Massachusetts: Pearson Education Inc., 2008
3)Stwertka, Albert. A guide to the elements. New York, New York: Oxford UP Inc., 2002.
4) Technetium. Thursday, February. 2009 <http.//en.wikipedia.org/wiki/Technetium>.
5)Winter, Mark. Web Elements. Monday, February. 2009.<http.//webelements.com/technetium/chemistry.html |
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