Mendelevium is a synthetic actinide. It is a radioactive transuranic element produced by bombarding einsteinium with alpha particles. The most stable isotope of mendelevium, Md-258, has a half-life of 51.5 days. The homologue of mendelevium is thulium.
Mendelevium News 2013-11-13 - (jalopnik) - How a supercharged beetle helped discover the element mendelevium