Lithium is a chemical element with symbol Li and atomic number 3. It is a soft, silver-white metal belonging to the alkali metal group of chemical elements. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly reactive and flammable.Symbol: Li
Atomic number: 3
Electron configuration: [He] 2s1
Atomic mass: 6.941 ± 0.002 u
Discoverers: Johan August Arfwedson