|Atomic mass||(260) amu|
Lawrencium is element 103, the last of the metals in the actinide series. It was discovered at the Lawrence Radiation Laboratory at the Berkeley campus at the University of California in 1961. By then, the Lawrence Radiation Laboratory had been the birthplace of an unprecedented string of new elements.
Lawrencium was made by bombardment of Californium and Boron in a chamber fitted with a copper conveyer. The new atoms were carried one at a time to a radiation detector for identification.