Periodic Table Seaborg

Sea of electrons, 304 Seaborg, Glenn T., 420 Second column of periodic table, 377 Second-row elements, bonding capacity. 281... 

Figure 4. Comparison ol periodic tables given by Paneth 42) and Seaborg 44).

Russian chemist Dimitrii Mendeleev who developed the Periodic Table of the chemical elements. Credit for the first synthesis of this element is given American chemists at the University of California lab in Berkeley, California under Glenn T. Seaborg in 1958, who used the nuclear reaction Es ( He, 2n) Md and the nuclear reaction Es ( He, n) Md. The longest half-life associated with this unstable element is 51 day Md,... 

Plutonium - the atomic number is. 94 and the chemical symbol is Pu. The name derives from the planet Pluto, (the Roman god of the underworld). Pluto was selected because it is the next planet in the solar system beyond the planet Neptime and the element plutonium is the next element in the period table beyond neptunium. Plutonium was first synthesized in 1940 by American chemists Glenn T. Seaborg, Edwin M. McMillan, Joseph W. Kennedy and Arthur C. Wahl in the nuclear reaction U( H, 2n) Np = P => Pu. The longest half-life associated with this unstable element is 80 million year Pu. 

Dr. Glenn T. Seaborg proposed the term actinide for the new heavy elements that were predicted to follow the lanthanide series (Z-57 to Z-71). Dr. Seaborg believed that the actinides would be difficult to discover, and he proposed they would be trivalent homo-logues to the elements in the lanthanide series in which the 4f orbitals would be filled. His team at the Lawrence Berkeley National Laboratory (LBNL), located at the University of California s Berkeley campus, separated Z-95 (americium) and Z-96 (curium) as trivalent homologues of two of the elements in the lanthanide series located just above them in the periodic table. 

There are several spaces in the Periodic Table between plutonium (element 94) and einsteinium (element 99). But by 1952 these had already been filled by scientists at Berkeley, using the cyclotron to bombard heavy nuclei with particles that, when captured, increased the nuclear mass. In 1944 Glenn Seaborg, Albert Ghiorso, and Ralph James made elements 95 and 96 this way. Kept secret until after the war, they were respectively called americium and curium. 

Figure 15.9 Glenn Seaborg points out seaborgium in the periodic table. (Figure also appears in color figure section.)...

Figure 15.9 Glenn Seaborg points out seaborgium in the periodic table.

When Mendeleev published his periodic table for the first time, there were 63 elements. After his death, the number of elements had increased to 86. This quick increase was the result of the periodic table, the most important systemization of chemistry. Although Mendeleev did not discover any new elements, the element with the atomic number 101 discovered by a committee of American scientists led by G.T Seaborg in 1955, was named mendelevium (Md) in honor of Dmitri Mendeleev. 

Glenn Theodore Seaborg created and isolated several elements larger than uranium in the 1940s. Seaborg reorganized the periodic table to its current form. 

The 100th element of the expanded Periodic Table was first sighted in the dust of a nuclear explosion set off in 1952 at Eniwetok atoll in the Pacific. When Enrico Fermi, one of great builders of the atomic age, was killed by cancer late in 1954, his fame was immortalized in the name of this new element, fermium. Finally, element No. 101 was created out of element 99 and named mendelevium. But this is not the end of element creation, for Seaborg predicated that within the next few years at least seven more elements would be synthesized. 

Future Periodic Table (reproduced with permission from G.T. Seaborg, J. Chem. Soc., Dalton Trans., 1996, 3904). 

Table 1. Predictions of the ground-state configurations of Gol danskii [37), Chaikkorskii [38), Taube [39) and Seaborg (5) for elements 121 to 127 and 159 to 168, using the principle of the extrapolation within the periodic table. The main quantum numbers [5g, 6/, Id, 8s) are not shown. This table is taken from Mann [3S)...

The next elements of the periodic table, starting with element 121 belong to a very long, unprecedented transition series which is characterized by the filling of not only the 6/ but also the 5g electrons. Seaborg (5) called these elements Super actinides. 

Seaborg s team suggested the name plutonium for the new element, in honor of the planet Pluto. The two elements just before plutonium in the periodic table had also been named for planets uranium for Uranus and neptunium for Neptune. 

Seaborg was warned not (o publish his new periodic table because it would ruin his scientific reputation. He is quoted as saying. sometime later, 1 didn t have any scientific reputation so I published it anyway. For a discussion of this and other interesting historical developments in actinide chemistry, see George Kauffman s review, Beyond Uranium" in Chem. Eng. News 1990, 68(47), 18-29. 

Glenn Seaborg A Human Side to the Modern Periodic Table... 

Glenn T. Seaborg, Nobel Laureate chemist and Chancellor of the University of California at Berkeley, is the co-discoverer of nine of the 102 chemical elements. He is the only man since Dmitri Mendeleev to have made a major change in the Periodic Table of the Elements—a change which led immediately to the discovery of the first element heavier than plutonium and subsequently to the discovery of another half dozen transuranium elements. 

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