Calcium
Calcium is the 20th element on the periodic table of elements and it is the fifth most abundant element in the earth's crust.[2] Some of its properties are listed below:[2]
| Atomic weight | 40.078 |
| Density (at 0oC) | 1.54 g/cm3 |
| Boiling point | 1757 K |
| Melting point | 1115 K |
Calcium is an alkaline Earth mineral. It is naturally found in bones, teeth, shells, rocks, and minerals. Calcium carbonate is a naturally occurring compound that is the basis for limestone, marble, and chalk. Stalagmites and stalactites in caves form from calcium carbonate precipitating out of solution.[3]
Calcium uses
Calcium is used as a reducing and/or alloying agent for metals[2]. It is used primarily in the creation of steel to improve the steel's mechanical properties. Historically, calcium was used to create lime (a calcium oxide and/or hydroxide compound), which was used as a building material. Lime is still used today in substances like paints, concrete, cement, and plaster.
Calcium compounds (such as calcium carbonate or calcium magnesium pills) are often used as calcium supplements for human consumption. Calcium carbonate is also used as an antacid for indigestion[3].
Calcium Carbonate as part of the Carbon Dioxide Cyle
Calcium carbonate compounds (limestone, shells, etc.) are natural carbon sinks in two ways:[4]
- The formation of carbonate (CO3) often involves the capture of CO2
- Calcium carbonate can react with carbon dioxide saturate water and for calcium bicarbonate (Ca(HCO3)2)
Through weathering and human activities, the calcium carbonate can be made to break down, releasing the stored carbon dioxide. Acidified solutions (e.g. acid rain) and heat (especially from human processign) are particularly good at breaking down calcium carbonate and bicarbonate into calcium oxide and carbon dioxide (and water, in the case of bicarbonate breakdown)[4].
Isotopes
Calcium has six isotopes found in nature:[2]
| Symbol | Natural Abundance |
|---|---|
| 40Ca | 96.941% |
| 42Ca | 0.647% |
| 43Ca | 0.135% |
| 44Ca | 2.086% |
| 46Ca | 0.004% |
| 48Ca | 0.187% |
Video
The video below is from the University of Nottingham's periodic videos project.[5] They have created a complete suite of short videos on every element on the periodic table of elements.
For Further Reading
- Periodic table of elements
- Carbon dioxide
- Greenhouse gas
- Metal
- Carbon capture and storage
- Or explore a random page
References
- ↑ Made internally by a member of the Energy Education team, with information from periodictable.com, Available: http://periodictable.com/Elements/001/index.html
- ↑ 2.0 2.1 2.2 2.3 Royal Society of Chemistry Periodic Table, Calcium [Online], Available: http://www.rsc.org/periodic-table/element/20/calcium
- ↑ 3.0 3.1 John Emsley, "Nature’s Building Blocks: An A-Z Guide to the Elements", Oxford University Press, New York, 2nd Edition, 2011.
- ↑ 4.0 4.1 John W. Morse, Rolf S. Arvidson, and Andreas Lüttge. "Calcium Carbonate Formation and Dissolution". Chemical Reviews, 2007, V.107 (2), pg 342-381.
- ↑ See more videos from the University of Nottingham on different elements here: http://www.periodicvideos.com/