Lawrencium is a radioactive synthetic chemical element with the symbol Lr (formerly Lw) and atomic number 103. In the periodic table of the elements, it is a period 7 d-block element and the last element of the actinide series. Chemistry experiments have confirmed that lawrencium behaves as the heavier homologue to lutetium and is chemically similar to other actinides.Symbol: Lr
Electron configuration: Rn 5f14 7s2 7p1
Atomic number: 103
Discovered: 1961
Melting point: 1,627 °C
Atomic mass: 262 u