Discovery date : 1937
Discovered by: Carlo Perrier and Emilio Segrè
Origin of the name: The name is derived from the Greek 'tekhnetos' meaning artificial.
Allotropes :
~>TECHNETIUM is a chemical element with symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive; none are stable.
| FACT BOX | |||
| Group | 7 | Melting point | 2157°C, 3915°F, 2430 K |
| Period | 5 | Boiling point | 4262°C, 7704°F, 4535 K |
| Block | d | Density (g cm−3) | 11 |
| Atomic number | 43 | Relative atomic mass | [98] |
| State at 20°C | Solid | Key isotopes | unknown |
| Electron configuration | [Kr] 4d55s2 | CAS number | 7440-26-8 |
| ChemSpider ID | 22396 | ChemSpider is a free chemical structure database | |
Technetium long tantalised chemists because it could not be found. We now know that all its isotopes are radioactive and any mineral deposits of the element had long disappeared from the Earth’s crust. (The longest lived isotope has a half life of 4 million years.) Even so, some technetium atoms are produced as uranium undergoes nuclear fission and there is about 1 milligram of technetium in a tonne of uranium. Claims in the 1920s to have found this element, or at least to have observed its spectrum, cannot be entirely discounted.
Technetium was discovered by Emilio Segrè in 1937 in Italy. He investigated molybdenum from California which had been exposed to high energy radiation and he found technetium to be present and separated it. Today, this element is extracted from spent nuclear fuel rods in tonne quantities.