Vital Statistics

• Strontium's atomic number is 38, meaning that the element has 38 protons in its nucleus, and an atomic radius of 215.1 pm. Sr exhibits an electron configuration of [Kr]5s2.
  
  

Physical Properties

• Elemental strontium metal naturally occurs as a silvery, soft metal. Because of its rapid oxidation on contact with air, the metal is typically covered with a yellowish coating of strontium oxide and stored in kerosene to avoid spontaneous decomposition.
  
  

Fireworks

• If sliced into thin strips, strontium metal ignites spontaneously in air. Strontium salts are used to give a bright red color to pyrotechnic materials and flares.
  
  

Nuclear Properties

• While there are a total of 20 known isotopes of strontium, the metal occurs naturally as a mixture of four stable isotopes. The most concerning isotope of the metal, 90Sr, is a product of nuclear fallout and is a long-lived high-energy beta radiation emitter with a half-life of 29 years. Used in nuclear-powered devices, this isotope of strontium poses a health hazard.
  
  

Mineral Sources

• Strontium is usually found in the minerals celestite and strontianite. Typically the element can be isolated from its mineral form by treating the mineral with hydrochloric acid, forming strontium chloride. The strontium chloride is then mixed with potassium chloride and electrolyzed to isolate strontium metal.