Elements beyond Uranium

The elements that lie beyond uranium in the periodic table are called transuranium elements. 

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Before it was known that elements beyond uranium were capable of existence, the heaviest known natural elements, thorium, protactinium and uranium, were placed in a sixth period of the periodic classification, corresponding to the elements hafnium, tantalum and tungsten in the preceding period. It was therefore implied that these elements were the beginning of a new, fourth transition series, with filling of the penultimate n = 6 level (just as the penultimate = 5... 

Apart from naturally occurring elements, there are now newly made elements beyond uranium. These constitute the transuranic series. All the elements in this series are radioactive. 

In 1934 Fermi decided to bombard uranium with neutrons in an attempt to produce transuranic elements, that is, elements beyond uranium, which is number 92 in the periodic table. He thought for a while that he had succeeded, since unstable atoms were produced that did not seem to correspond to any known radioactive isotope. I le was wrong in this conjecture, but the research itself would eventually turn out to be of momentous importance both for physics and for world history, and worthy of the 1938 Nobel Pri2e in Physics. 

One of the major advances of science in the first half of this century was the synthesis of ten elements beyond uranium. Glenn T. Seaborg participated in the discovery oj most of these, a sufficient tribute to his outstanding ability as a scientist. For the first such discoveries, those of neptunium and plutonium, he shared with Professor Edwin M. McMillan the Nobel Prize in Chemistry for 1951. 

Seaborg GT, Loveland WD. 1990. The elements beyond uranium. New York John Wiley Sons, Inc. 

G. T. Seaboig and W. D. Loveland, The Elements Beyond Uranium, Wiley-Interscience, New York, 1990. 

Seaborg, G.T. and W.D, Loveland The Elements Beyond Uranium, John Wiley Sons, New York, NY, 1990. 

The first scientific attempts to prepare the elements beyond uranium were performed by Enrico Fermi, Emilio Segre, and co-workers in Rome in 1934, shortly after the existence of the neutron was discovered. This group of investigators irradiated uranium with slow neutrons and found several radioactive products, which were thought to be due to new elements. However, detailed chemical studies by Otto Hahn and Fritz Strassman in Berlin showed these species were isotopes of the known elements created by the fission of uranium into two approximately equal parts (see Chap. 11). This discovery of nuclear fission in December of 1938 was thus a by-product of man s quest for the transuranium elements. 

Neptunium, the element beyond uranium, was named after the planet Neptune because this planet is beyond the planet Uranus for which uranium is named. 

The effort to synthesize artificial elements beyond uranium began in 1934, went on for several years with a number of apparent successes, and then came to an abrupt halt in 1938 when nuclear fission was discovered and scientists realized that they had not found a single new element in all that time - the entire four-year search for transuranium elements had in fact been the study of fission fragments. 

With this, the goals of those who first sought artificial elements beyond uranium were realized. The understanding of nuclear behavior was deepened by the discovery of nuclear fission, and the periodic system was extended and clarified by the synthesis of transuranium elements. 

Seaborg, Glenn T., and Loveland, Walter D. (1990). The Elements beyond Uranium. New York Wiley. 

Most of the chemical elements are metals and many of them are little used some are so rare that only the man-made variety exists on earth, and that applies to the radioactive elements beyond uranium, which is element number 92 in the periodic table. It is also true for lighter elements such as technetium (element 43) and promethium (element 61). Yet such elements have their uses technetium in medical diagnostics, promethium in miniature batteries for pacemakers. Hopefully, most people will never need to encounter either metal, but some radioactive metals should be a part of everyone s life and especially... 

The chemistry of actinides is more complicated due to the existence of greater range of oxidation states for these metals. Moreover, all these metals are radioactive and therefore, their accessibility for laboratory investigations is limited. The elements beyond uranium are all man-made elements and are made by nuclear-chemical methods. 

G.T. Seaborg andW.D. Loveland, The Elements beyond Uranium, Wiley, 1990, pp. 71-78 (f electrons). 

Transition metals several series of elements in which inner orbitals (d or / orbitals) are being filled. (12.13 18.1) Transuranium elements the elements beyond uranium that are made artificially by particle bombardment. (21.3)... 

In the period between 1940 and 1961, 11 transuranium elements were discovered by researchers from the University of California at Berkeley (UCB). The term transuranium element refers to elements beyond uranium (atomic numbers greater than 92) in the periodic table. The periodic table is a chart that shows how chemical elements are related to each other. All transuranium elements are unstable or radioactive. Radioactive elements emit energy or particles as they decay into more stable atoms. One of these elements was berkelium. 

There have been some predictions that element 114 will be relatively stable in comparison with many other elements beyond uranium in the periodic table. Predict the maximum oxidation state of this element. Based on the trends in the oxidation states of other members of its group, is it likely that this oxidation state will be the dominant one. ... 

All actinide elements of the 5/series are radioactive. Th and U are long lived and occur in minerals that also contain their radioactive decay products. Elements beyond uranium are made artificially, by bombardment with neutrons or with nuclei. Uranium and plutonium are used as nuclear fuels. 

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