Tennessine

Tennessine is a synthetic element; it has symbol Ts and atomic number 117. It has the second-highest atomic number and the joint-highest atomic mass of all known elements, and is the penultimate element of the 7th period of the periodic table. It is named after the U.S. state or region of Tennessee where key research institutions involved in its discovery are located. The discovery of tennessine was officially announced in Dubna, Russia, by a Russian–American collaboration in April 2010, which makes it the most recently discovered element. One of its daughter isotopes was created directly in 2011, partially confirming the experiment's results. The experiment was successfully repeated by the same collaboration in 2012 and by a joint German–American team in May 2014. In December 2015, the Joint Working Party of the International Union of Pure and Applied Chemistry (IUPAC) and the International Union of Pure and Applied Physics (IUPAP), which evaluates claims of discovery of new elements, recognized the element and assigned the priority to the Russian–American team. In June 2016, the IUPAC published a declaration stating that the discoverers had suggested the name tennessine, a name which was officially adopted in November 2016. Tennessine may be located in the "island of stability", a concept that explains why some superheavy elements are more stable despite an overall trend of decreasing stability for elements beyond bismuth on the periodic table. The synthesized tennessine atoms have lasted tens and hundreds of milliseconds. In the periodic table, tennessine is expected to be a member of group 17, the halogens. Some of its properties may differ significantly from those of the lighter halogens due to relativistic effects. As a result, tennessine is expected to be a volatile metal that neither forms anions nor achieves high oxidation states. A few key properties, such as its...