This element is the lightest alkali metal and it is very reactive. This metal is used for the production of dry cells and storage batteries (for cell phones, car batteries, etc.). The carbonate of this metal is used for the treatment of some mental decease.
This element is a noble gas which is gas at room temperature. It is characterized by its brilliant green and orange spectral lines. This noble gas is used in fluorescent light bulbs, luminous signs, high-speed photography.