Ca2+: is the chemical symbol for the ion of Calcium that has a positive charge due to the loss of 2 electrons from its outer electron shell. It is a major part of many biochemical processes in the body and is a very important element in keeping the body functioning.
Cited: Bentor, Yinon. Chemical Element.com - Calcium. Dec. 1, 2006 http://www.chemicalelements.com/elements/ca.html.