strontium

Name strontium
Symbol Sr
Atomic Weight 87.62
Atomic Number 38
CAS ID 7440-24-6
Group Number 2
Group Name Alkaline Earth Metal
Period Number 5
Origin of Name Named after Strontian, Scotland
Year Discovered 1790
Discovery Credits Recognized as an element by A. Crawford at Edinburgh, Scotland. Isolated in 1808 by Sir Humphry Davy at London, UK.
Class Metallic
Color Silvery White
Standard State Solid at 77 F & 298 K
Description Silvery shiny, soft metal obtained by high temperature reduction of SrO with Al. Protected as bulk metal by oxide film but will burn in air and reacts with water. Used in special glass for TV and VDUs, in fireworks and flares to give red color.  The Sr87 isotope used in Rb-Sr age dating.

Diagnostic tests: 
Strontium is usually detected by the crimson flame coloration. If large quantities of calcium are present, than a spectroscope can be used to distinguish the Sr coloration.

Strontium compounds become alkaline (turns pink litmus paper blue with a drop of water) after ignition before a blowpipe flame with the exceptions of phosphates and silicates. Note that Ca and Mg minerals also give an alkaline reaction.

In solution, the presence of strontium (in the absence of barium) is proved by the heavy white precipitate formed by the addition of dilute H2SO4.

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