Lawrencium
Lawrencium. A radioactive actinide discovered in 1961. It has the atomic symbol Lr, atomic number 103, and atomic weight of 257. There are two isotopes with mass number 257 or 258, and mass number 256.
MegaLexica
Lawrencium. A radioactive actinide discovered in 1961. It has the atomic symbol Lr, atomic number 103, and atomic weight of 257. There are two isotopes with mass number 257 or 258, and mass number 256.