Ununpentium(Uup) is the temporary name of a synthetic superheavy element in the periodic table that has the atomic number 115, thus it is sometimes referred to as element 115. It is placed as the heaviest member of group 15 (VA). The problem is that an isotope stabe enough to confirm its position is not known at this time. It was first observed in 2003 and only about 30 atoms of ununpentium have been synthesized to date, with just 4 direct decays of the parent element having been detected. Four consecutive isotopes are currently known, 287-290Uup, with 289 having the longest measured half-life (~220 milliseconds). It is possible that 290 has a longer half-life, but only one decay has been seen, so the information is poor and not accepted as accurate.
On February 2, 2004, synthesis of ununpentium was reported in Physical review by a team composed of Russian scientists at the Joint Institute for Nuclear Research and American scientists at the Lawrence Livermore National Laboratory. The scientists reported that they had bombarded americium 243 with calcium 48 ions to produce four atoms of element 115. These atoms decayed by emission of alpha-particles to ununtrium in approximately 100 milliseconds. The collaboration further strengthened their claim for the discovery of the element by conducting chemical experiments on the decay daughter, an isotope of Dubnium(Db268). In experiments in June 2004 and December 2005, the Dubnium isotope was successfully identified by milking the Db fraction and measuring any spontaneous fission. Both the half life decay mode were confirmed for the proposed Db268 which lends support to ununpentium as the parent nuclei.
Element 115 is projected to be the third member of the 7p series of non-metals and the heaviest member of group 15 (VA), just after bismuth. Each member of this group is known to portray the group oxidation state of +V but with differing stability. For nitrogen, the +V state is very difficult to achieve due to the lack of low-lying d orbitals and the inability of the small nitrogen atom to accommodate five ligands. The +V state is well represented for phosphorus, arsenic, and antimony. With bismuth it is rare because of the reluctance of the 6s2 electron to participate in bonding. This effect is known as the inert pair effect and is commonly linked to relativistic stabilization of the 6s orbitals. It is expected that element 115 will continue along these lines and portray only +III and +I oxidation states. It is expected that the chemistry of ununpentium will be related to bismuth. In this regard it is expected to undergo oxidation only as far as the trioxide. Oxidation with the more reactive halogens should form trihalides. The less-oxidizing, heavier halogens, may only be able to promote the formation of the monohalides.
Try this link for more information about ununpentium. Here on Universe Today we have a great article about the newest element known to man; copernicium.
Source: Wikipedia
Comments on this entry are closed.