LIST OF HEAVY ELEMENTS.

Thetransuranium elements(also known astransuranic elements) are the chemical elementswith atomic numbersgreater than 92 (the atomic number of uranium). All of these elements are unstable and decay radioactivelyinto other elements. Overview Periodic table with elements colored according to the half-life of their most stable isotope. Elements which contain at least one stable isotope. Slightly radioactive elements: the most stable isotope is very long-lived, with a half-life of over four million years. Significantly radioactive elements: the most stable isotope has half-life between 800 and 34,000 years. Radioactive elements: the most stable isotope has half-life between one day and 103 years. Highly radioactive elements: the most stable isotope has half-life between several minutes and one day. Extremely radioactive elements: the most stable isotope has half-life less than several minutes. Of the elements with atomic numbers 1 to 92, all can be found in nature, having stable (such as hydrogen), or very long half-life(such as uranium) isotopes, or are created as common products of the decay of uranium and thorium (such as radon) — only technetium, of the elements below uranium, was man-made for its discoveryin 1936. All of the elements with higher atomic numbers, however, have been first discovered in the laboratory, with neptunium, plutonium, americium, curium, berkeliumand californiumlater also discovered in nature. They are all radioactive, with a half-lifemuch shorter than the age of the Earth, so any atoms of these elements, if they ever were present at the Earth's formation, have long since decayed. Trace amounts of these six elements form in some uranium-rich rock, and small amounts are produced during atmospheric tests of atomic weapons. The Np, Pu, Am, Cm, Bk, and Cf are generated from neutron capturein uranium ore with subsequent beta decays(e.g. 238 U+ n→ 239 U→ 239 Np→ 239 Pu). Transuranic elements can be artificially generated synthetic elements, via nuclear reactorsor particle accelerators. The half lives of these elements show a general trend of decreasing as atomic numbers increase. There are exceptions, however, including dubniumand several isotopes of curium. Further anomalous elements in this series have been predicted by Glenn T. Seaborg, and are categorised as the “ island of stability.” [ 1 ] Heavy transuranic elements are difficult and expensive to produce, and their prices increase rapidly with atomic number. As of 2008, weapons-grade plutonium cost around $4,000/gram, [ 2 ]and californiumcost $60,000,000/gram. [ 3 ]Due to production difficulties, none of the elements beyond californium have industrial applications,[ citation needed]and of them, only einsteiniumhas ever been produced in macroscopic quantities. [ 4 ] Transuranic elements that have not been discovered, or have been discovered but are not yet officially named, use IUPAC's systematic element names. The naming of transuranic elements may be a source of controversy. Discovery and naming of transuranium elements So far, essentially all the transuranium elements have been produced at three laboratories: *.The Radiation Laboratory (now Lawrence Berkeley National Laboratory) at the University of California, Berkeley, led principally by Edwin McMillan, Glenn Seaborg, and Albert Ghiorso, during 1945-1974: *.93. neptunium, Np, named after the planet Neptune, as it follows uraniumand Neptune follows Uranusin the planetary sequence(1940). *.94. plutonium, Pu, named after the dwarf planet Pluto, following the same naming rule as it follows neptunium and Pluto follows Neptune in the pre-2006 planetary sequence (1940). *.95. americium, Am, named because it is an analog to europium, and so was named after the continent where it was first produced (1944). *.96. curium, Cm, named after Pierreand Marie Curie, famous scientists who separated out the first radioactiveelements (1944).