Mendelevium is a synthetic element with the symbol Md and atomic number 101. It was first discovered in 1955 by a team of scientists at the Lawrence Berkeley National Laboratory while bombarding einsteinium with alpha particles. Mendelevium is part of the actinide series and is classified as a heavy metal. This element is highly radioactive and has no stable isotopes. The most common isotope, Md-258, has a half-life of about 51.5 days. Mendelevium is primarily used for research purposes, particularly in the fields of nuclear chemistry and physics, due to its limited availability and high radioactivity.