Magnesium is a metallic element with the symbol Mg. It has 12 electrons, 12 protons, and 12 neutrons. Mg is found in dolomite, carnallite, sea water, and the Earth's crust. Some key uses of magnesium include in flares, pyrotechnics, bombs, airplanes, and missiles due to its ability to burn brightly. It is a soft, silver-white metal that is not toxic but poses a fire risk when in its metallic form.