Calcium
Karlyn East
December 13, 2010
Calcium (Ca), an extraordinary element, is an alkaline earth metal which is in
group two and period four in the periodic table. Calcium’s name derives from the Latin
words calx and calcis which mean lime (Barbalace). It was discovered in 1808 by Sir
Humphrey Davy in London, England. After learning that Berzelius and Pontin, two
chemists in Sweden, prepared calcium amalgam by electrolyzing lime in mercury, Sir
Humphrey Davy was able to isolate the impure substance. He did this by the
electrolysis of a mixture of lime (CaO) and mercuric oxide (HgO). Though calcium metal
was not truly available to people until the beginning of the 20th century (Barbalace).
Calcium’s atomic number on the periodic table of elements is twenty, and its true
atomic mass is 40.08 g. It has twenty protons and twenty neutrons, and limestone is a
common name for it (Ca(CO)3). Calcium has a melting point of 850 Co, and a boiling
point of 1440 Co (Knapp). Its density is 1.54 grams per cubic centimeter, and calcium is
a fairly soft metal with a shiny silver surface when first cut. The surface quickly becomes
dull as calcium reacts with oxygen to form a coating of white or gray calcium oxide
(Knapp). Calcium also reacts with the halogens (Knapp). Calcium compounds are used
in a soil to improve its condition and to balance any acidity. This means keeping the soil
materials clumped together into crumb sized pieces so that the soil drains well and air
can get in. Several compounds of calcium are used for this purpose. The fastest acting
compound is calcium hydroxide (Newton). Calcium is essential to both plant and animal
life. In humans, it makes up about two percent of our body weight (Knapp). About 99
percent of the calcium in a person’s body is found in bones and teeth. It also helps
control the way the heart beats and makes bones and teeth hard and resistant to wear
(Knapp).
Calcium is most commonly found in the earth’s core and it is the fifth most
abundant element found there (Knapp). Its abundance is estimated to 3.64 percent, and
it is also the fifth most abundant element in the human body (Knapp). It is contained in
the soft tissue, in fluids within the tissue and in the structure of every animal’s skeleton.
Calcium does not occur as a free element in nature because it is too active and always
exists as a compound (Knapp). There are 8 main compounds that contain calcium they
are: Calcium arsenate (Ca3(AsO4)2), calcium carbide (CaC2), calcium carbonate
(CaCO3), calcium cyanide (CaCN2), calcium oxide (CaO), calcium phosphide (Ca3P2),
calcium silicate (CaSiO3), and calcium sulfate (CaSO4) (Barbalace). Calcium arsenate is
a white powder that is slightly soluble in water. It is very toxic to inhale and to digest. It
is used widely as an insecticide and genocide (CAMEO Chemicals: Calcium arsenate).
Calcium carbide is colorless, but most of the material is produced industrially, and is
somewhat impure, giving it a black or grayish-white color, depending on the quality. The
main use for calcium carbide is in the production of the flammable gas acetylene (Hill).
Calcium carbonate is a dietary supplement used when the amount of calcium taken in
the diet is not enough. Calcium is needed by the body for healthy bones, muscles,
nervous system, and heart. Calcium carbonate also is used as an antacid to relieve
heartburn, acid indigestion, and upset stomach. It is available with or without a
prescription (MedlinePlus Drug Information). Calcium cyanamide is used as a fertilizer,
pesticide, and in the manufacture of other chemicals. It is irritating to the eyes, skin,
and respiratory tract in humans (Technology Transfer Network Air Toxics Website).
Calcium oxide, which is also known as burnt lime or quicklime, is a white powdery
compound. It is not really used other than as a weapon because when this compound is
mixed with water its temperature rises very quickly (Barbalace). Calcium phosphide is
used as a incendiary bomb and usually appears as a red powder with some gray bumps
(Knapp). Calcium silicate is also a white powdery substance, and is used as a anti
caking agent and an antacid (Occupational Safety and Health Guidelines: Calcium
silicate). Calcium sulfate is a calcium salt which occurs abundantly in the natural
environment and also appears as a byproduct of some industrial processes. The
chemical formula for this material is CaSO4, and it comes in two primary forms: an
anhydrous form and a hydrous form. The different forms have a wide range of
applications, ranging from making casts for treatment of fractured limbs to creating
works of art (Smith). Calcium can be found just about anywhere in the world and is not
necessarily concentrated in one certain part of the world. In is found in all limestone
which is also found all over the planet. It also has a lot of medical upside as well.
Calcium is the main makeup of a couple of vitamins and pills that are very beneficial to
the human body. For example, the coral calcium pill that reduces arthritis, reduces
acidic pH levels, and gives the body better mental function (Juntunen).
Calcium has four levels of energy in its atomic structure. In the first level there
are two electrons, in the second level there are eight electrons, in the third level there
are eight, and in the fourth level there are two electrons (1s2 2s2 2p6 3s2 3p6 4s2 ). Its
oxidation state is +2 (Gagnon). Calcium also has many isotopes but only four stable and
common ones (See appendix figure 1). There are also some common reactions that
take place with Calcium. The reaction between Calcium and water for instance is a very
common and helpful reaction (Ca (s) + 2H2O (g) -> Ca(OH)2 (aq) + H2 (g)). This reaction
forms calcium hydroxide that dissolves in water as a soda, and hydrogen gas. This is
helpful because calcium is a dietary requirement for all organisms apart from some
insects and bacteria. Calcium is largely responsible for water hardness, and may
negatively influence toxicity of other compounds. Elements such as copper, lead and
zinc are much more toxic in soft water ( Lenntech Water treatment & purification ).
Isolating Calcium is down by something called a Downs Cell. It is an electrochemical
cell, which is a device capable of either deriving electrical energy from chemical
reactions, or facilitating chemical reactions through the introduction of electrical energy
(Newton). This will and can electrolyze calcium chloride to produce calcium and
chloride. It is the same method to produce elements such as sodium and magnesium
(Newton).
To separate calcium from the other ions in its group there is a simple method that
can be used. Taking a polyatomic ion that is insoluble, such as sulfide, and combining it
into a test tube that contains an aqueous solution of nickel and calcium (Cole). The
sulfide would react with the nickel that would produce precipitate solid and leaving
calcium in the aqueous solution (Cole). A test tube with cobalt and calcium would also
work with the polyatomic ion, sulfide, in the same exact way as it did with nickel. For
these experiments wear safety goggles, and do not touch the metals with bare hands
since the moisture could make the chemicals corrosive. Put the mixtures in a tube or jar
for disposal later by dumping them into a separate container because they are a hazard
because of how reactive they are with water. Also the metals can clog up the drain and
should not be dumped down the drain.
Calcium is a very unique element that has some very interesting characteristics.
It is very important to the body and our environment, and is one of the most common
elements in the world. Without calcium the human body could not function the way that
it is properly supposed to, and that might be calcium’s most important characteristic.
Works Cited
Lenntech Water treatment & purification . Calcium (Ca) and water. 1998-2009. 15
December 2010 <http://www.lenntech.com/periodic/water/calcium/calcium-andwater.htm>.
CAMEO Chemicals: Calcium arsenate. 1998. 15 December 2010
<http://cameochemicals.noaa.gov/chemical/2765>.
Cole, Thompson/Brooks. Solubitites of Ionic Compounds. 11 December 2010
<http://www.professormeyer.com/images/solubility%20chart.jpg>.
Gagnon, Steve. The Element Calcium. 15 December 2010
<http://education.jlab.org/itselemental/ele020.html>.
Hill, Adam. WiseGeek. 14 October 2010. 15 December 2010
<http://www.wisegeek.com/what-is-calcium-carbide.htm>.
Juntunen, Valarie. Health Benefits of Coral Calcium. 12 December 2010
<http://www.ehow.com/facts_4865705_health-benefits-coral-calcium.html>.
Knapp, Brian. "Elements Calcium and Magnesium." Danbury,CT: Atlantic Europe
Publishing Company, 2002. 28-29.
MedlinePlus Drug Information. 1 May 2010. 15 December 2010
<http://www.nlm.nih.gov/medlineplus/druginfo/meds/a601032.html>.
Newton, David E. "Chemical elements from Carbon to Krypton." Farmington Hills,
Michigan: The Gale Group, 1999. 87-96.
Occupational Safety and Health Guidelines: Calcium silicate. 15 December 2010
<http://www.osha.gov/SLTC/healthguidelines/calciumsilicate/recognition.html>.
Smith, S.E. WiseGeek. 2010 9 November . 15 December 2010
<http://www.wisegeek.com/what-is-calcium-sulfate.htm>.
Technology Transfer Network Air Toxics Website. 6 Novemeber 2007. 15 December
2010 <http://www.epa.gov/ttn/atw/hlthef/calciumc.html>.
Kenneth Barbalace. Periodic Table of Elements - Calcium - Ca.
EnvironmentalChemistry.com. 1995 - 2010. 12/13/2010
http://EnvironmentalChemistry.com/yogi/periodic/Ca.html
Appendix
(Barbalace)
Figure 1
Decay
Nuc-
Atomic
lide
Mass
Abun
NN
%
Ca34
34.014
14
Syn
Ca35
35.0048
15
Syn
Ca36
Ca37
35.9931
36.9859
16
17
Syn
Syn
Spin
Half Life
DM
DT
BR
Energy
%
(MeV)
0+
0+
3/2+
50ms
ε
K35
15.610
50ms
ε+P
Cl33
10.860
102ms
ε+P
Ar35
102ms
ε
K36
181.1ms
ε+P
Ar36
181.1ms
ε
K37
11.639
57
9.320
10.990
76
9.781
Ca38
37.9763
18
Syn
0+
440ms
ε
K38
6.743
Ca39
38.9707
19
Syn
3/2+
859.6ms
ε
K39
6.531
Ca40
39.9626
20
96.941
0+
Stable
Ca41
40.9623
21
Syn
7/2-
103000y
ε
K41
0.421
Ca42
41.9586
22
0.647
0+
Stable
Ca43
42.9588
23
0.135
7/2-
Stable
Ca44
43.9555
24
2.086
0+
Stable
β-
Sc45
0.257
4.536d
β-
Sc47
1.992
0+
>6E 18y
β-
Ti48
4.272
Syn
3/2-
8.718m
β-
Sc49
5.262
Syn
0+
13.9s
β-
Sc50
4.966
Ca45
44.9562
25
Syn
7/2-
162.61d
Ca46
45.9537
26
0.004
0+
Stable
Ca47
46.9546
27
Syn
7/2-
Ca48
47.9525
28
0.187
Ca49
48.9557
29
Ca50
49.9575
30
(Barbalace).
(Barbalace)
Flow Chart
NiCaSnCo
SO4
CoSO4
O2
SnO2
NiCaSn
NiCa
S
NiS
Ca