Radium is a chemical element with the symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, known as alkaline earth metals.

Radium is unnecessary for living organisms, and adverse health effects are likely incorporated into biochemical processes because of its radioactivity and chemical reactivity. Currently, other than its use in nuclear medicine, radium has no commercial applications; formerly, it was used as a radioactive source for radioluminescent devices and also in radioactive quackery for its supposed curative powers. Today, these former applications are no longer in vogue because radium's toxicity has become known, and less dangerous isotopes are used instead in radioluminescent devices.

Alkali Metals and Alkaline Earth Metals

The alkali metals (group 1) have very similar properties: they are all shiny, soft, highly reactive metals at standard temperature and pressure and readily lose their outermost electron to form cations with charge +1. The alkaline earth metals are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure.

The alkali metals are a group (column) in the periodic table consisting of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).