A synthetic transuranic metallic element having over 20 isotopes and isomers with mass numbers ranging from 242 to 260. The longest-lived isotope has mass number 257 and a half-life of approximately 100 days. Atomic number 100; melting point 1527°C; valence 3.
A radioactive, metallic chemical element, one of the actinides, produced by intense neutron bombardment of plutonium, as in a cyclotron: symbol, Fm; at. no. 100
A synthetic, radioactive metallic element of the actinide series that is produced from plutonium or uranium. Its most stable isotope is Fm 257 with a half-life of approximately 100 days. Atomic number 100.
Origin of fermium
- After Enrico Fermi
From American Heritage Dictionary of the English Language, 5th Edition
- Named for Enrico Fermi.