nobelium

A radioactive transuranic element in the actinide series artificially produced in trace amounts. Its most long-lived isotopes are No-255 with a half-life of 3.1 minutes, and No-259 with a half-life of 58 minutes. Atomic number 102; valence 2, 3. cross-reference: Periodic Table.

a transuranic chemical element (symbol No) with an atomic number of 102.

a radioactive transuranic element synthesized by bombarding curium with carbon ions; 7 isotopes are known