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12. MagnesiumName: Magnesium
Magnesium is the eighth most abundant element in the earth's crust although not found in it's elemental form. It is a Group 2 element. Group 2 elements are called alkaline earth metals. Magnesium tarnishes slightly in air, and finely divided magnesium readily ignites upon heating in air and burns with a dazzling white flame. Normally magnesium is coated with a layer of oxide, MgO, that protects magnesium from air and water.Magnesium metal burns with a very bright light. Magnesium is an important element for plant and animal life. Chlorophylls are porphyrins based upon magnesium. The adult human daily requirement of magnesium is about 0.3 g per day. The name originates from the Greek word for a district in Thessaly called Magnesia. Joseph Black in England recognized magnesium as being an element in 1755, Sir Humphrey Davey electrolytically isolated pure magnesium metal in 1808 from a mix of magnesia and HgO and A. A. B. Bussy prepared it in coherent form in 1831. Magnesium is the eighth most abundant element in the earth's crust. It is an alkaline earth metal and therefore does not occur uncombined with other elements. It is found in large deposits of magnesite, dolomite, and other minerals. Magnesium metal and alloys are highly flammable in their pure form and melts when it is a powder. Magnesium metal quickly reacts exothermically upon contact with air or water and should be handled with care. It is good to wear safety glasses. The bright white light (including ultraviolet) produced by burning magnesium can damage the eyes. Water should not be used to extinguish magnesium fires, because it can actually feed the fire. Carbon dioxide fire extinguishers should not be used either, because magnesium can burn in carbon dioxide. Quick links
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