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Hassium holds its place at the table.

For the first time, researchers have studied the chemistry of the element hassium hassium (hăs`ēəm, häs`–), artificially produced radioactive chemical element; symbol Hs; at. no. 108; mass number of most stable isotope 265; m.p., b.p., sp. gr., and valence unknown. , confirming its location on the periodic table.

Hassium, with 108 protons in each atom, is the heaviest element yet to have its chemical properties analyzed. First created in 1984, hassium doesn't exist in nature--it must be made by combining the nuclei of lighter elements.

Suspecting that hassium has properties similar to osmium osmium (ŏz`mēəm), metallic chemical element; symbol Os; at. no. 76; at. wt. 190.2; m.p. 3,045±30°C;; b.p. 5,027±100°C;; sp. gr. 22.57 at 20°C;; valence usually +0 to +8.  and other so-called group 8 elements, chemists placed hassium on the periodic table directly below osmium. Such placement, however, relied only on theoretical predictions, says Heino Nitsche of the Lawrence Berkeley (Calif.) National Laboratory. No one had actually observed hassium behavior--until now.

Nitsche and his colleagues in Berkeley worked with researchers at the Paul Scherrer Institute The Paul Scherrer Institute (PSI) is a multi-disciplinary research institute which belongs to the Swiss ETH-Komplex covering also the ETH Zurich and EPFL. It was established in 1988 by merging in 1960 established EIR (Eidgenössisches Institut für R  in Villigen and the University of Bern The University of Bern is a university in the Swiss capital of Bern. It was founded in 1834. As one of the German-speaking universities in Switzerland its official name is Universität Bern, although it is frequently referred to in the French form, Université de Berne.  in Switzerland and the Institute of Nuclear Chemistry in Mainz, Germany.

The team recently built and installed an instrument at the UNILAC heavy-ion accelerator in Darmstadt, Germany, that can detect and analyze hassium. When the researchers slammed atoms of the artificial isotope isotope (ī`sətōp), in chemistry and physics, one of two or more atoms having the same atomic number but differing in atomic weight and mass number. The concept of isotope was introduced by F.  curium-248 with magnesium-26 atoms, they ended up with at least six molecules of hassium.

Hassium has a half-life of just 9 seconds, but that's long enough to obtain crucial data, says Nitsche. For example, hassium atoms reacted with oxygen to form hassium oxide molecules that condensed con·dense  
v. con·densed, con·dens·ing, con·dens·es
1. To reduce the volume or compass of.

2. To make more concise; abridge or shorten.

3. Physics
 at a temperature consistent with the behavior of group 8 elements, says Nitsche. The team measured other properties of hassium, such as the energy released as it decays.

The work would have pleased the early chemists who contributed to the periodic table, notes Nitsche, because it "shows that the structure of the periodic table holds even to these elements that they couldn't imagine at the time."
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Title Annotation:periodic table of chemical elements
Publication:Science News
Article Type:Brief Article
Date:Jun 23, 2001
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