Technetium is a silvery-gray radioactive metal with atomic number 43 and symbol Tc. It is the lowest atomic number element without any stable isotopes and an important thing to know is that every form of it is radioactive. Technetium was the first element to be produced artificially and all its isotopes are radioactive.
Nearly all is produced synthetically, and only small amounts originate in nature. It occurs naturally in the spontaneous fission from uranium ore or by neutron capture in molybdenum ores.
The element discovery in nature was erroneously reported in 1925 by the German chemists I. W. and W. K. Noddack, which named it Masurium. The first artificial element was discovered in 1937 by C. Perrier and E. G. Segrè in a small piece of molybdenum foil, after it was bombarded with deuterons in a cyclotron at the Univ. of California at Berkeley and sent to them by E. O. Lawrence.
Element 43 (technetium) was predicted by Mendeleyev on the basis of the newly created periodic table. He also suggested that it should be almost like manganese and named it eka-manganese.
It is named after the Greek word technetos, meaning "artificial".
In the periodic table, technetium is positioned in the center of the second row transition series, between manganese and rhenium. Because of the lanthanide contraction, the chemistry is much more like that of rhenium, its third-row congener, than it is like that of manganese. Its location in the center of the periodic table gives technetium a rich and diverse chemistry. Oxidation states −1 to +7 are known, and complexes with a wide variety of coordination numbers and geometries have been reported.
Technetium was once very rare and expensive but is now obtained in modest quantities from nuclear reactor fission products. Although the spectra of some stars show that they contain technetium, it has not been found on earth, occurring naturally.
It was first used in radioactive isotope medical tests, for example as a radioactive tracer that medical equipment can detect in the human body.
Periodic table of elements video