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Rubidium is an element<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref>in the Alkali metals class of the periodic table.  It is so chemically active that it is never found free (in elemental form) in nature, and can sometimes catch fire on mere exposure to air.

Rubidium is an element<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref>in the Alkali metals class of the periodic table.  It is so chemically active that it is never found free (in elemental form) in nature, and can sometimes catch fire on mere exposure to air.

It was discovered by Robert Bunsen and Gustav Kirchoff, using their newly invented spectroscope.  It was identified by a previously unseen red spectral line in the analysis of mineral water from a German spa.  The name comes that color.

It was discovered by Robert Bunsen and Gustav Kirchoff, using their newly invented spectroscope.  It (along with [[cesium]]) was identified by a previously unseen red spectral line in the analysis of mineral water from a German spa.  The name comes from that color.

==References==

==References==