Symbol Md. A radioactive metallic transuranic element belonging to the actinoids; a.n. 101; mass number of the first discovered nuclide 256 (half-life 1.3 hours). Several short-lived isotopes have now been synthesized. The element was first identified by Albert Ghiorso, Glenn Seaborg (1912–99), and associates in 1955.
http://www.webelements.com/webelements/elements/text/Md/key.htm Information from the WebElements site
Subjects: Chemistry — Physics.