Discovery of Element

In June 1974, members of the Joint Institute for Nuclear Research in Dubna, U.S.S.R., reported their discovery of Element 106, which they reported to have synthesized. Glenn Seaborg was part of this group, and the element was named in his honor. Seaborgium is often still referred to as Element 106 because the international committee in charge of names changed the rules. They decided retroactively it couldn t be named after a living person. 

The isotope produced was the 20-hour 255Fm. During 1953 and early 1954, while discovery of elements 99 and 100 was withheld from publication for security reasons, a group from the Nobel Institute of Physics in Stockholm bombarded 238U with 160 ions, and isolated a 30-min alpha-emitter, which they ascribed to 250-100, without claiming discovery of the element. This isotope has since been identified positively, and the 30-min half-life confirmed. 

The lanthanides comprise the largest naturally-occurring group in the periodic table. Their properties are so similar that from 1794, when J. Gadolin isolated yttria which he thought was the oxide of a single new element, until 1907, when lutetium was discovered, nearly a hundred claims were made for the discovery of elements... 

During the nineteenth century the discovery of elements increased as chemists began to adopt quantitative methods. At the beginning of the nineteenth century, perhaps 26 elements were known. One hundred years later, at the beginning of the present century, over 81 elements were known. Over twice as many elements were discovered in that one century as were discovered in all of time before. 

Our research at Berkeley has resulted in the discovery of element 94, demonstration of the slow neutron fissiona-bility of its isotope 94239, discovery and demonstration of the slow neutron fissionability of U23 3, spontaneous fission measurements on these isotopes, discovery of 93237, isolation of and nuclear measurements on U23, study of the chemical properties and methods of chemical separation of element 94, demonstration of the presence of small concentrations of 94 in nature and much related information. 

There had been some confusion about the discovery of element number 43 until in 1937 Perrier and Segre succeeded in producing it by deuteron irradiation of molybdenum placed in a cyclotron. A Japanese chemist by the name of Ogawa believed that he had succeeded in discovering this element in 1908, but in vain. Afterwards, in 1925 the Noddack group claimed to have discovered this element, but their claim turned out to be false. 

The interest of alchemists in urine was driven by a search for a yellow pigment known as India Yellow, which is produced in the urine of cows fed with mango leaves. This interest, then, led to the discovery of elemental phosphorus. 

After the announcement and publication of the discovery of element 116 (and 118), controversy arose as to the actual production of these elements as reported. On July 27, 2001,... 

CMS—Discovery of Elements 113 and 115. http //www-cms.llnl.gov/ell3 115/about.html (accessed October 23,... 

Names of Scientists Associated with Discoveries of Elements of Periodic Table, by Dr. JohnAndraos. http //www.careerchem. CO m/NAMED/Elements-D iscoverers.pdf >... 

G. T. Seaborg and E. M. McMillan. The Nobel Prize for Chemistry for 1951 was awarded jointly to Glenn T. Seaborg and Edwin M. McMillan, both of the University of California, for their discoveries in the chemistry of the transuranium elements." Dr. Seaborg is chairman of the Division of Physical and Inorganic Chemistry at the University of California. Dr. McMillan worked at the Massachusetts Institute of Technology in connection with radar development, collaborated with J. Robert Oppenheimer in organizing the Los Alamos Scientific Laboratory, and did the initial work that led to the discovery of elements heavier than uranium. 

This was why the discovery of element 94 by Seaborg and colleagues was so sensitive. In 1941 the Berkeley team told the US government that one isotope of the new element, plutonium-239, could be split with slow neutrons even more efficiently than could U. Again, a grapefruit-sized lump could make a bomb. 

For many years, we have been following the footsteps of the discoverers of chemical elements. We have traveled extensively to places associated with the various elements— to the sites of mines, laboratories, museums and other locations where work on the discovery of elements was carried out or where artifacts are displayed and interpreted. Under the title Rediscovery of the Elements (1), we have compiled guides to these sites to allow students, educators, and other curious people to follow along, whether actually or vicariously. The project includes extensive photographs as well as directions and coordinates. 

FERMIUM. ICAS 7440-72-4). Chemical element symbol Fm. at. no. 100. at. wt. 257 (mass number of the most stable isotope), radioactive metal of the Actinide series, also one of the Transuranium elements. During Ihe period 1953- 1954. a group of scientists at the Nobel Institute of Physics (Stockholm) bombarded U with l60 ions, producing and isolating a 30-min alpha emitter. Ibis was called -5"l(X). However, discovery of element 100 was noi claimed at that time. Subsequently, the isotope was identified and the 30-miu half-lile conlirmed. Both fermium and einsteinium were formed in a thermonuclear explosion that occurred in the South Pacific in 1952. The elements were identified by scientists from the University of California s Radiation Laboratory, the Argonne National Laboratory, and die Los Alamos Scientific Laboratory. It was observed that very heavy uranium isutopes lhal resulted from the action of the instantaneous neutron flux cm uranium (conlaincd in the explosive device) decayed lo form Es and Fm, The probable electronic configuration of... 

The years after World War II led to the discovery of elements 97-103 and the completion of the actinide series. While the story of the discovery of each of these elements is fascinating, we shall, in the interests of brevity, refer the reader elsewhere (see References) for detailed accounts of most of these discoveries. As an example of the techniques involved, we shall discuss the discovery of element 101 (mendelevium). 

Contemporaneously with the Berkeley experiments, Zvara et al. (1969, 1970), working at Dubna, produced 3.2 + 0.8 s 259104 by the Pu/ Ne, 5n) reaction. The chloride of this spontaneously fissioning activity was shown using gas chromatography to be slightly less volatile than Hf, but more volatile than the actinides. An international group of reviewers (Barber et al., 1992) has determined that the Berkeley and Dubna groups should share the credit for the discovery of element... 

The reported discoveries of elements 114 and 116 do not connect the observed decays to the region of known nuclei. Devise an experimental program to make this connection or to establish the Z of the 114 and 116 nuclei. 

In 1950, Seaborg, Thompson, and Ghiorso reported the discovery of element 97, berkelium (Bk) ... 

All this suggests that the comparative history of the discovery of elements 43 and 75 constitutes a suitable case study to investigate the boundaries of chemistry and... 

It is only in recent times that a polemic arose about the naming of element 43. See P. H. M. Van Assche, The ignored discovery of element Z=43, Nuclear Physics A480 (1988) 205-214 and G. Herrmann, Technetium or masurium - a comment on the history of element 43, Nuclear Physics A505 (1989) 352-360. 

This continued to block the discovery of element 93, even though everyone now knew just where to look for it. In the spring of 1939 Edwin McMillan and Emilio Segre irradiated uranium in the Berkeley cyclotron to form the 23-minute uranium of process 3. They detected a new 2-day beta activity, but because the activity had... 

In this section, we present results dealing with the discovery of elements 107 to 112 using cold fusion reactions based on lead and bismuth targets. A detailed presentation and discussion of the decay properties of elements 107 to 109 and of elements 110 to 112 was given in previous reviews [15,20,21], Presently known nuclei are shown in the partial chart of nuclides in Figure 2. 

Today, one century after Ernest Rutherford and Frederick Soddy postulated that in the radioactive decay one chemical element transmutes into a new one, we know of 112 chemical elements. The discoveries of elements 114 and 116 are currently waiting to be confirmed and experimentalists are embarking to discover new and heavier elements. Now where are superheavy elements located on a physicist s chart of nuclides and on the Periodic Table of the Elements - the most basic chart in chemistry ... 

The separations of the recently discovered elements hafnium (Z = 72) and rhenium (Z = 75) from immense quantities of ores were guided by x-ray spectra. Care must obviously be taken in such cases so that the investigator does not mistake a wavelength characteristic of a known element for one presumably arising from the new element. (The premature announcements of the discovery of elements 43 and 61 in nature were very possibly the results of incorrect assignments of lines in the x-ray spectra.)... 

---