This is a halogen element, lustrous solid, which volatilizing at ordinary temperatures into a blue-violet gas with an irritating odor. Ample amounts of this element are required by the human body for the proper function of the thyroid gland.
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 classified as an actinide and it is solid at room temperature. It is a synthetic transuranic element and can be produced in kilogram quantities. It is used in smoke detectors and as a portable source of gamma rays.