Periodic Table -> Calcium


Calcium Details

Calcium Symbol: Ca

Calcium Atomic Number: 20

Calcium Atomic Weight: 40.08

What is Calcium?

Calcium (atomic number 20, symbol Ca) is an alkaline earth metal and one of the most abundant elements found in the Earth's crust in terms of mass. This soft gray element is rather hard, and it is important for life on earth, especially for cell physiology whereby the calcium ion Ca2+ moves out and into the cytoplasm, signaling different cellular processes. It is the main component in the mineralization of shells and bones, and the most abundant element of all by mass in many living organisms. Calcium is an important constituent of teeth, leaves, and bones, and calcium carbonate is found in stalactites and stalagmites. It makes up some 3.22 percent of the oceans, air, and earth. There are different natural forms of the metal, including gypsum, limestone, and fluorite. Apatite is a chlorophosphate or fluorophosphate of the element.

In the 1st century, the Romans produced calx, which is lime, but it was only in 1808 when calcium was discovered. Pontin and Berzelius electrolyzed lime in mercury as to prepare calcium amalgam. Impure material was isolated by Davy. Nowadays, electrolysis of CaCl2 is used to prepare the metal, the temperature being just above its melting point.

Calcium has a boiling point at 1484°C, melting point at 839°C, and a valance of 2. It forms different compounds such as calcium chloride, calcium hypochorite, calcium cyanamide, calcium sulfide, and others. One of calcium’s common compounds is calcium carbonate, which forms quicklime when heated and added to water. Slaked lime is thus formed, which represents an inexpensive material with application in the chemical industry. Limestone, marble, and chalk are different forms of this compound.

Slaked lime or calcium hydroxide is produced when limestone is heated at temperature above 825 °C, water being added carefully to it. It is used in a variety of chemical refinery processes. Mixing sand and lime produces mortar, which is then made into plaster through the uptake of carbon dioxide.
Mixing lime with different compounds makes a main component of Portland cement. Hydroxylapatite is formed by combining calcium and phosphate, and this compound forms the mineral component of the teeth and bones of animals and humans. The mineral component of some of the corals can be used to produce hydroxylapatite. Water percolating through soluble carbonates, such as limestone, dissolves rocks partially, causing the formation of stalagmites, stalactites, cave formations, and hard water.

There is a variety of applications of calcium and its compounds, one being as a decarbonizer, desulfurizer, and deoxidizer. Thus, it is used in various nonferrous and ferrous alloys. It is also used as a reducing agent when thorium, zirconium, uranium, and other metals are extracted. Calcium is also used to make mortars and cements for the construction sector. In the food industry, calcium is used to produce cheese, with calcium ions influencing rennin’s activity to result in the coagulation of milk. As an alloying agent, calcium is also used to produce lead, copper, beryllium, aluminum, and magnesium alloys. Calcium compounds also have different applications, with limestone, lime, mortar, and cement being produced from calcium carbonate. It also has application in the manufacturing of glass and has optical and chemical uses in toothpastes. Calcium arsenate is a calcium compound used in insecticides. Limewater, which is a solution of calcium hydroxide, helps detect carbon dioxide by bubbling it through the hydroxide solution. When carbon dioxide is present, it turns cloudy.

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