Calcium

What is Calcium?

Calcium is a chemical element necessary for all living things. It is abundant in many non-living things, such as soil, water, and things necessary for survival. Some of the products of calcium include bones, sea shells, teeth, and cave stalactites.

Calcium is the fifth most plentiful element in the earth’s crust. It also ranked fifth in the list of the most abundant dissolved ions in seawater. In the human body, calcium is the most abundant metallic element. About 99% of calcium is found in the teeth and bones.

Where is Calcium obtained?

The reactive nature of calcium is the reason why it is not found in free form. It is present in the earth’s crust in the form of silicate, fluoride, sulfate, carbonate, and borate. 

• Calcium carbonate – The sources of calcium carbonate are calcite, limestone, chalk, and marble.
• Calcium sulfate – The sources for calcium sulfate are gypsum and anhydrite.
• Calcium phosphate – The source of calcium phosphate is apatite.
• Calcium fluoride – The source for calcium fluoride is fluorite or fluorspar.
• Calcium can also be found in alumino silicates and silicates.
• Natural waters contain calcium too, such as seawater, which contains calcium sulfate and calcium carbonate. 
• Some organisms have calcium compounds in their skeletons or shells, such as calcium carbonate in oyster shells and corals. 

History of Calcium

Sir Humphry Davy, a Cornish chemist, was the first person to isolate calcium in 1808. There were other scientists who made attempt to discover calcium in the form of calcium amalgam and they were Jöns Jacob Berzelius and Magnus Pontin.

They use the process called electrolysis using a mixture of mercury oxide and lime. Sir Humphry Davy conducted the same electrolysis on calcium amalgam but added more lime resulting in more amalgam.

Through the process, he was able to distill away mercury and only calcium was left. The successful isolation of calcium paved the way for further studies, and eventually revealing the significant of calcium in the survival of living things.

Classification, Properties and Characteristics of Calcium

Calcium’s physical and chemical properties are the same as those of barium and strontium. It is a poor conductor of electricity. With its structure, it is harder than lead but soft enough to be cut with a knife.

It is reactive to atmospheric oxygen. When heated, calcium reacts with other elements like carbon, phosphorus, sulfur, boron, and hydrogen. It is less reactive but more expensive than sodium. It dissolves in liquid ammonia, giving the solution a dark blue hue.

Lewis Dot Structure of Calcium

Bohr’s Atomic Model of Calcium

Atomic Data of Calcium

Physical Properties of Calcium

Color	silvery white/silvery gray
Odor	odorless
Taste	bitter/sour
Atomic Mass	40.078
Weight	40.078
Density	1.54
Atomic Radius	197 pm
Ionization Energy	6.113 eV
Covalent Radius	174 pm
Ionic Radius	0.099 nm
Electronic Gain Enthalpy	192 kJ/mol
Electron Negativity	1
Electron Affinity	2.369 (kJ mol−1)
Melting Point	842°C, 1548°F, 1115 K
Boiling Point	1484°C, 2703°F, 1757 K

Chemical Properties of Calcium

Atomic Number	20
Group	2
Period	4
Block	s
Electronic Configuration	[Ar] 4s2
Combustion	Ignites when heated in air or in oxygen
Chemical Reactivity	Highly reactive with acids
Valency of Element	2

Different States of Calcium

As an alkali earth metal, calcium remains in a solid state at room temperature. When placing a chunk of calcium in a container of distilled water, calcium starts to create bubbles, producing hydrogen gas. It will eventually form a cloudy white precipitate of calcium hydroxide.

What are the common uses of calcium? 

• Various calcium compounds are used in the construction industry, specifically in the making of construction materials. Plaster, or so-called plaster of Paris, is created through the use of gypsum or calcium sulfate. It is a heavy white powder mixed with water. Once it hardens, it forms a cast that is used to stabilize fractured bones.
• Calcium carbonate, also known as limestone, is used as cement and other related construction materials. When limestone is heated, it releases carbon dioxide and leaves quicklime, or calcium oxide. When mixed with water, it forms calcium hydroxide, also known as slaked lime, a substance necessary for making cement. It is also used as a water treatment agent to significantly reduce the acidity of water and as a soil conditioner.
• Calcium hydroxide, or slaked lime, is mixed with sand. The mixture results in the pulling in of carbon dioxide from the air. Once it hardens, it forms a lime plaster.
• Pure calcium metal is used as a reducing agent to be used in making other types of metals like uranium, thorium, and zirconium.
• Calcium is used as an alloying agent for magnesium alloys, copper, lead, and aluminum.
• It is also used as a deoxidizer, decarburizer, and desulfurizer for various types of ferrous and non-ferrous alloys.
• Calcium plays an important role in human nutrition. It provides strength and a solid structure to the skeleton. It is also the mineral responsible for maintaining healthy teeth and bones.
• Calcium is significant for plant growth.
• Calcium plays a vital role in the making of paper, paint, glass, glazes, and sugar.
• Calcium ions play a vital role in ion exchange, which is vital in maintaining calcium balance in the bone and blood.
• Calcium in the blood is responsible for various bodily processes such as hormone signaling, nerve signal transmission, coagulation, and muscle contraction.

Price of Calcium

Calcium is a bit pricey. It costs $20 per 100 grams.

Interesting facts about Calcium

• Of all the metallic elements, calcium is the most plentiful in the human body. An adult has around 1 kilogram of calcium, and 99% of it is found in the teeth and bones.
• Don’t you know that modern humans were not the first to use calcium to create things? Primitive people were able to use it and a perfect example is the Pyramid of Egypt. It was built using limestone blocks, which are crystalline calcium carbonate. The blocks of the later pyramids were held together with the use of lime-based mortar known as gypsum, a calcium sulfate dihydrate, and lime, which is a calcium oxide.
• Don’t you know that if you burn lime using oxyhydrogen flame, it creates a brilliant light? During the 1800s, it was used to light theater stages. Thus, the name limelight.

Frequently Asked Questions

References

1. https://www.rsc.org/periodic-table/element/20/calcium
2. https://www.britannica.com/science/calcium
3. https://www.lenntech.com/periodic/elements/ca.htm
4. https://www.livescience.com/29070-calcium.html
5. https://www.thoughtco.com/calcium-element-facts-606472
6. https://www.chemicool.com/elements/calcium.html
7. https://education.jlab.org/itselemental/ele020.html
8. https://www.vedantu.com/chemistry/calcium
9. https://chemistrytalk.org/calcium-element/
10. https://byjus.com/chemistry/calcium/