Gizmo

treeves writes "Radioactive nuclei that hang around for a mere half-minute before falling apart hardly seem stable. Yet compared with the fleeting lifetimes of their superheavy atomic neighbors, the roughly 30-second period that transpired from creation to disintegration of four atoms of a newly discovered isotope of element 108 qualifies those atoms as rock solid. Theoretical physicists predicted years ago that some nuclei of elements much more massive than uranium should survive for a relatively long time — possibly long enough to probe their chemical properties — if they could be synthesized. On the chart of nuclides, theoreticians pinpointed a region with coordinates corresponding to 114 protons and 184 neutrons and indicated that nuclei with those "magic" numbers of subatomic particles should lie at the center of an island of stability. The nuclear longevity, according to the models, is due to the closing of proton and neutron shells, which renders the particles stable against spontaneous fission much the same way that a filled outer electron shell endows noble gases with chemical inertness. Experimentalists, though, haven't yet found a route to reach the center of the island."

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