RUBIDIUM

Because rubidium is a much larger atom than lithium or sodium, it gives up its outer valence electron easily, thus becoming a positive ion (oxidation state = Ru+). Rubidium forms numerous compounds, but only a few are useful. One of the main uses for rubidium is as a getter in vacuum tubes used in early radios, TVs, and cathode-ray tubes. When rubidium gas is placed in sealed glass cells along with an inert gas, it becomes a rubidium-gas cell clock. Because of the consistent and exact frequency (vibrations) of it atoms, it is a very accurate timekeeper. Rubidium and selenium are used in the manufacture of photoelectric cells, sometimes called electric eyes. Rubidium is a very caustic alkali (base) with a high pH value that makes it an excellent reducing agent (highly electropositive) in industry and chemical laboratories. A unique use is its ability to locate brain tumors. It is a weak radioisotope able to attach itself to diseased tissue rather than healthy tissue, thus making detection possible.