Roentgenium is a synthetic element with the symbol Rg and atomic number 111. It was first created in 1994 by a team of Russian and American scientists at the Joint Institute for Nuclear Research in Dubna, Russia. Roentgenium is a member of the group 11 elements, which also includes gold and silver. Due to its short half-life, it is not found in nature and must be produced in a laboratory. This element is named in honor of Wilhelm Conrad Roentgen, the discoverer of X-rays. Roentgenium is highly radioactive, and its most stable isotope has a half-life of about 1.5 milliseconds. Because of its instability, very little is known about its chemical properties, but it is expected to behave similarly to other elements in its group.