| Resources: Lawrence Livermore Laboratory, www.llnl.gov |
Researchers at Lawrence Livermore National Laboratory, working with other American and Russian scientists, recently discovered element 117, a superheavy element that fills in row seven of the Periodic Table. The two-year discovery process, which was driven by berkelium’s 320-day half-life, began with 250 days spent irradiating 22 mg of berkelium (element 97), followed by 90 days to separate and purify it. The material was then bombarded by heavy ions for 150 days. The final product, six atoms of element 117, each with a half life of 78 msec. The research team also observed 11 new neutron-rich isotopes. The element, temporarily named ununseptium (“un-un-sept” for 1-1-7), has the symbol Uus and is the 20th element discovered since 1940. It could take a few years before it gets its official name.