The chemistry of the metal calcium

Calcium is one of the important elements that are essential for human beings, plants and animals. Calcium is an alkaline earth metal and 5th abundant element in the earth crust. The chemical properties, physical properties and uses are discussed in this article.

The Element:

Calcium is an alkaline earth metal. It is the 5th abundant element in the earth crust. It is the 3rd most abundant metal in the earth crust. The chemical symbol of this material is Ca. It is the 20th element in the periodic table and belongs to group 2 in the periodic table. The name calcium is derived from the Latin word calx. The meaning of Calx is lime. The important ore for this metal is limestone. It is a silver-grey coloured material. This element is first discovered in 1808 by a British chemist called Sir Humphry Davy. This material is the known lightest metal. It tends to react with both water and air. It is solid at room temperature. The element calcium is very much required by all living organisms. This is an essential element for all human beings, plants and animals. It is present in the skeleton and teeth of human beings. Seawater is also having calcium as calcium chloride. Calcium is available in many food products like milk, milk products, vegetables and nuts. Because of the reactive nature of calcium, it is not available in nature as calcium. It is available in nature as various chemical compounds. Calcium is available as limestone, gypsum and fluorite.

The Properties:

Let us discuss some important properties of calcium metal.
  1. Every atom of calcium will have twenty electrons, 20 neutrons and 20 protons. A calcium atom will have 2 electrons in its outer orbital and it will always show a tendency to lose these two electrons to attain stability by forming a cation Ca^++.

  2. The atomic number of calcium is 20. The atomic number of an element is the number of protons it is having in its atom.

  3. The atomic weight is 40. Atomic weight is the total number of protons and neutrons that are available in its atom.

  4. The ionisation potential of this material is 589.8 kJ/mol. What is ionisation potential? The energy required to remove an electron from an isolated atom is known as ionisation potential. This is also called ionisation energy. The energy required for removing the most loosely bound electron is known as the first ionisation energy. Removing an atom from an ion that already lost an electron is known as second ionisation energy.

  5. The electronegativity of calcium is 1. What is electronegativity? This is a measure of the tendency of the atom to attract electrons that are shared between two ions. The value of this character will range between 0.7 to 4. Among the known elements fluorine is having the highest electronegativity and the value is 4.

  6. Melting point of calcium is 840 degrees centigrade and the boiling point is 1484 degrees centigrade. We all know that the melting point is the temperature at which a solid will become liquid at atmospheric pressure. The boiling point is the temperature at which a liquid becomes gas at atmospheric pressure.

  7. Calcium reacts with halides and forms calcium halides. For example, calcium reacts with hydrogen chloride to form calcium chloride.
    Ca + 2 HCl --> CaCl2+H2.

  8. Calcium reacts with hydrogen carbonate to form calcium carbonate.
    Ca + H2CO3 --> CaCO3 + H2

  9. Calcium will react with water and forms calcium Hydroxide.
    Ca + 2H2O --> Ca (OH)2 + H2

  10. Calcium will react with oxygen to form calcium oxide
    2Ca + O2 --> 2CaO

  11. Calcium is available in ten isotopic forms. In these isotopes, Ca 40 is the normal calcium which is very stable. Ca-41, Ca-42. Ca-43, Ca-44, Ca- 46 and Ca-48 are stable isotopes of calcium. Ca-45 and Ca- 47 are having less half-life and Ca-49 is the most unstable isotope of calcium which is having just 8.7 minutes of half life. Isotopes are the atoms of the same element with same atomic number but different atomic weights. In other words same atoms with different number of neutrons in its nucleus are called isotopes of the element.

The Uses:

The following are some of the important uses and applications of calcium.
  1. The human bones and teeth are consisting of calcium. Calcium is very much required for maintaining the strength of our bones and teeth. The element is essential for the movement of muscles in carrying messages from the human brain to all the other parts of the body. The element is also required for our body to release hormones and enzymes that are required for our body.

  2. This element is used in making steel by adding it to iron as it has a tendency to react with oxygen and sulphur.

  3. Many compounds of calcium are used in the food industry and pharmaceutical industry as additives.

  4. Calcium compounds are having their applications in construction activities. Calcium silicate is used in making bricks that will withstand very high temperatures and are used in furnaces and kilns that are maintained at very high temperatures. Plaster of Paris is also a very well-known strong compound used in setting fractured bones.

  5. Calcium is a good alloying agent and is used in making alloys with aluminium, copper, magnesium and lead. What is an alloy? An alloy is nothing but a mixture of two or more elements and in these components at least one will be metal. It is a mixture but not a compound.


Thus calcium plays a very important role in our lives both in food products as well as health products. It is also vital even in these advanced technology days as there is no replacement for the calcium compounds that are used in bone jointing and resetting.


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