Roentgenium is the 111th element on the Periodic Table of the Elements. The element was discovered by the Heavy Ion Research Laboratory, located in Germany, in 1994. The element was named after Wilhelm Röntgen, the scientist who discovered x-rays. The actual element has 111 protons, 111 electrons, and 170 neutrons. Roentgenium's atomic mass is 281 and is a metal. It is only used for research purposes and is very harmful, due to its high radioactivity. Its half-life lasts for 23 seconds.