Symbol: Md
Atomic number: 101
Atomic weight: (256)
Radioactive metallic transuranic element. Belongs to the actinoid series. Only known isotope, Md-256 has a half-life of 1.3 hours. First identified by Glenn T. Seaborg, Albert Ghiorso and associates in 1955. Alternative name unnilunium has been proposed. Named after the 'inventor' of the periodic table, Dmitri Mendeleev.