The chemical element (Symbol Ca), with an atomic number 20. It is a soft, silvery-white alkaline earth metal which occurs naturally as carbonate in limestone and as silicate in many rocks.
The chemical element (symbol Mg) with an atomic number of 12. It is a light, easily flammable, silvery-white alkaline earth metal.
(countable) An atom of this element.
A light silver-white metallic element of atomic number 12, malleable and ductile, quite permanent in dry air but tarnishing in moist air. It burns, forming (the oxide) magnesia, with the production of a blinding light (the so-called magnesium light) which is used in signaling, in pyrotechny, or in photography where a strong actinic illuminant is required. Its compounds occur abundantly, as in dolomite, talc, meerschaum, etc. Symbol Mg. Atomic weight, 24.305. Specific gravity, 1.75.
An elementary substance; a metal which combined with oxygen forms lime. It is of a pale yellow color, tenacious, and malleable. It is a member of the alkaline earth group of elements. Atomic weight 40. Symbol Ca.
a light silver-white ductile bivalent metallic element; in pure form it burns with brilliant white flame; occurs naturally only in combination (as in magnesite and dolomite and carnallite and spinel and olivine)
a white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animals
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray solid which bears a close physical resemblance to the other five elements in the second column (group 2, or alkaline earth metals) of the periodic table: all group 2 elements have the same electron configuration in the outer electron shell and a similar crystal structure.
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air.