Solubility of the carbonate in water containing carbon dioxide is high, which causes the formation of caves with stalactites and stalagmites and is responsible for hardness in water. Calcium from limestone is an important element in Portland cement. When mixed with sand, it hardens mortar and plaster by taking up carbon dioxide from the air. Quicklime (CaO), which is made by heating limestone that is changed into slaked lime by carefully adding water, is the great base of chemical refinery with countless uses. Its natural and prepared compounds are widely used. It is also used as an alloying agent for aluminum, beryllium, copper, lead, and magnesium alloys, and serves as a "getter" for residual gases in vacuum tubes, etc. The metal is used as a reducing agent in preparing other metals such as thorium, uranium, zirconium, etc., and is used as a deoxidizer, desulfurizer, or decarburizer for various ferrous and nonferrous alloys. The metal has a silvery color, is rather hard, and is prepared by electrolysis of fused chloride and calcium fluoride (to lower the melting point).Ĭhemically it is one of the alkaline earth elements it readily forms a white coating of nitride in air, reacts with water, burns with a yellow-red flame. Apatite is the fluorophosphate or chlorophosphate of calcium. Never found in nature uncombined, it occurs abundantly as limestone, gypsum, and fluorite. Atomic radius of Aluminum (Al) 184 pm: 14: Atomic radius of Silicon (Si) 210 pm: 15: Atomic radius of Phosphorus (P) 180 pm: 16: Atomic radius of Sulfur (S) 180 pm: 17: Atomic radius of Chlorine (Cl) 175 pm 18: Atomic radius of Argon (Ar) 188 pm: 19: Atomic radius of Potassium (K) 275 pm: 20: Atomic radius of Calcium (Ca) 231 pm: 21: Atomic. It is an essential constituent of leaves, bones, teeth, and shells. Potassium (K) has a greater atomic radius than that of Calcium (Ca) because when we move down a group, the atomic radius increases and when we move from. SourcesĬalcium, a metallic element, is fifth in abundance in the earth's crust, of which it forms more than 3%. After learning that Berzelius and Pontin prepared calcium amalgam by electrolyzing lime in mercury, Davy was able to isolate the impure metal. Though lime was prepared by the Romans in the first century under the name calx, the metal was not discovered until 1808.
The shell of the chicken egg is primarily calcium carbonate.įrom the Latin word calx, lime.
0 kommentar(er)
