Calcium
Links
Visual Elements: Calcium
http://www.chemsoc.org/viselements/pages/calcium.html
Image, animation, source, uses, and physical information.
It's Elemental: Calcium
http://education.jlab.org/itselemental/ele020.html
Basic physical and historical information.
ChemicalElements.com: Calcium
http://www.chemicalelements.com/elements/ca.html
Basic information, atomic structure, and isotopes.
Wikipedia: Calcium
http://www.wikipedia.org/wiki/Calcium
Properties of the element, including its history, applications, and charateristics.
EnvironmentalChemistry.com: Calcium
http://environmentalchemistry.com/yogi/periodic/Ca.html
Atomic structure, chemical and physical properties, and table of nuclides.
WebElements: Calcium
http://www.webelements.com/webelements/elements/text/Ca/key.html
Extensive information on history, uses, occurrence, compounds, and properties of the element.
Lenntech: Calcium
http://www.lenntech.com/Periodic-chart-elements/Ca-en.htm
Physical data, chemical properties, and health effects.