Lawrencium
Lawrencium, a radioactive, metallic chemical element. It does not occur in nature. Lawrencium was first produced in 1961 by a team of scientists headed by Albert Ghiorso of the University of California at Berkeley. They produced the element by bombarding californium atoms with boron ions in a linear accelerator. The longest-lived isotope, lawrencium 260, has a half-life of about 3 minutes. The element is named for Ernest O. Lawrence, a United States physicist.
Symbol: Lr. Atomic number: 103. Lawrencium has 8 known isotopes: Lr-253 through Lr-260. It is a transuranium element belonging to the actinide series of the Periodic Table and has a valence of +3.