Mendelevium
. Mendelevium, symbol Md, artificially created radioactive element with an atomic number of 101. Mendelevium is one of the transuranium elements in the actinide series of the periodic table . Named for the Russian chemist Dmitry Mendeleyev , mendelevium-256 was discovered in 1955 at the University of California, Berkeley; it was produced by bombarding einsteinium -253 with alpha particles accelerated in a cyclotron (see Particle Accelerators ). The isotope produced had a half-life of about 1.3 hours. The most stable isotope, mendelevium-258, has a half-life of 54 days. See also Radioactivity .