Wikipedia:Today's featured article/October 9, 2009



Ununoctium is the temporary IUPAC name for the transactinide element having the atomic number 118. On the periodic table of the elements, it is a p-block element and the last one of the 7th period. Ununoctium is currently the only synthetic member of group 18. It has the highest atomic number and highest atomic mass of all discovered elements. The radioactive ununoctium atom is very unstable, and since 2002, only three atoms (possibly four) of the isotope have been detected. While this allowed for very little experimental characterization of its properties and possible compounds, theoretical calculations have allowed for many predictions, including some very unexpected ones. For example, although ununoctium is a member of group 18, it is probably not a noble gas like all the other group 18 elements. It was formerly thought to be a gas but is now predicted to be a solid under normal conditions. In late 1998, Polish physicist Robert Smolanczuk published calculations on the fusion of atomic nuclei towards the synthesis of superheavy atoms, including element 118. His calculations suggested that it might be possible to make element 118 by fusing lead with krypton under carefully controlled conditions. (more...)

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