Lr+-+Lawrencium

jacobmedia type="custom" key="3199944"media type="custom" key="3227480" Name: Lawrencium Symbol: LR Atomic Number: 103 Atomic Mass: 262 Standard State:presumably a solid at 298 K Group name: none Period in Periodic Table: 7 Color: unknown, but probably metallic and silvery white or grey in appearance Classification: Metallic

lawrencium is a synthetic "rare earth metal" which does not occur in the environment. Element 103, lawrencium, was discovered in 1961 by Ghiorso and others in Berkeley, California, USA, who target with boron ions. They obtained perhaps two micrograms. Several lawrencium isotopes including those with masses 253, 254, 255, 256, 257, 258, 259, and 260 are known now.