Actinide, atomic number 102.
Nobelium is a synthetic chemical element with symbol No and atomic number 102. It is named in honor of Alfred Nobel, the inventor of dynamite and benefactor of science. A radioactive metal, it is the tenth transuranic element and is the penultimate member of the actinide series.
Symbol No. Atomic mass 259.0 u. Group 3, period 7. Electron configuration [Rn] 5f14 7s2. Electrons per shell 2, 8, 18, 32, 32, 8, 2. State at room temperature: Solid. Melting point 826.9 °C, boiling point unknown. Discovered by Joint Institute for Nuclear Research.
Element data from Wikipedia, CC BY-SA 3.0.