Technetium is a chemical element. It has the chemical symbol Tc. It has the atomic number 43. The color of technetium is silvery-grey. It is radioactive. It is a crystaline metal. In chemistry it is placed in a group of metal elements named the transition metals. The chemistry of technetium is somewhere between rhenium and manganese.
The isotope 99mTc is used in nuclear medicine. It is used for many diagnostic tests. It has a short half-life. 99Tc is used as a source of beta particles without emitting gamma rays. The ion that has oxygen and technetium bonded together (TcO4-) is named the pertechnetate ion. The pertechnetate ion could be used as to prevent anodic corrosion in steel.
Before the element was found, many of the properties of element 43 were predicted by Dmitri Mendeleev. Mendeleev saw a gap in his periodic table. He named the element in the gap ekamanganese. In 1937 the technetium isotope 97Tc was the first element to be artificially produced. This gave the element its name. In Greek τεχνητος means "artificial". Most technetium made on Earth is a by-product of fission of uranium-235 in nuclear reactors. It is extracted from nuclear fuel rods. On earth, technetium occurs naturally only in uranium ores as a product of spontaneous fission. The amount of technitium in the ore is very small but has been measured. No isotope of technetium has a half-life longer than 4.2 million years (98Tc). This means that its detection in red giants in 1952 helped support the theory that stars can produce heavier elements. it is the first man made element in periodic table