mendelevium

noun2

1. •
   A radioactive metallic transuranic chemical element (symbol Md) with atomic number 101, which is artificially produced in a particle accelerator.

   • Seven new elements were discovered with the 60-inch cyclotron: 85 (astatine), 93 (neptunium), 94 (plutonium), 96 (curium), 97 (berkelium), 98 (californium), and 101 (mendeleevium). — 1963
2. •
   An atom of this element.