Calcium

Calcium, ₂₀Ca
Calcium
Appearance	dull gray, siller; wi a pale yellae tint
Standard atomic weight Ar, std(Ca)	40.078(4)
Calcium in the periodic cairt
	potassium ← calcium → scandium
Atomic nummer (Z)	20
Group	group 2 (alkaline yird metals)
Period	period 4
Block	s-block
Element category	Alkaline yird metal
Electron confeeguration	[Ar] 4s2
Electrons per shell	2, 8, 8, 2
Pheesical properties
Phase at STP	solit
Meltin pynt	1115 K (842 °C, 1548 °F)
Bylin pynt	1757 K (1484 °C, 2703 °F)
Density (near r.t.)	1.55 g/cm3
when liquid (at m.p.)	1.378 g/cm3
Heat o fusion	8.54 kJ/mol
Heat o vapourisation	154.7 kJ/mol
Molar heat capacity	25.929 J/(mol·K)
Atomic properties
Oxidation states	+1, +2 strangly basic
Electronegativity	Pauling scale: 1.00
Ionisation energies	1st: 589.8 kJ/mol ; 2nd: 1145.4 kJ/mol ; 3rd: 4912.4 kJ/mol ; (more) ;
Atomic radius	empirical: 197 pm
Covalent radius	176±10 pm
Van der Waals radius	231 pm
	Colour lines in a spectral rangeSpectral lines o calcium
Ither properties
Naitural occurrence	primordial
Creestal structur	face-centred cubic [[File:face-centred cubic\|frameless\|alt=Face-centred cubic creestal structur for calcium\|upright=0.23\|Face-centred cubic creestal structur for calcium]]
Speed o soond thin rod	3810 m/s (at 20 °C)
Thermal expansion	22.3 µm/(m·K) (at 25 °C)
Thermal conductivity	201 W/(m·K)
Electrical resistivity	33.6 nΩ·m (at 20 °C)
Magnetic orderin	diamagnetic
Magnetic susceptibility	+40.0·10−6 cm3/mol
Young's modulus	20 GPa
Shear modulus	7.4 GPa
Bulk modulus	17 GPa
Poisson ratio	0.31
Mohs haurdness	1.75
Brinell haurdness	170–416 MPa
CAS Nummer	7440-70-2
History
Diskivery an first isolation	Humphry Davy (1808)
Main isotopes o calcium
γ	–
	view; talk; edit; \| references

Calcium is the chemical element wi seembol Ca an atomic nummer 20. Calcium is a saft gray alkaline yird metal, an is the fift-maist-abundant element bi mass in the Yird's crust. Calcium is the fift-maist-abundant dissolved ion in seawatter bi baith molarity an mass, efter sodium, chloride, magnesium, an sulphate.^[5]

Calcium is essential for livin organisms, in parteecular in cell pheesiology, whaur muivement o the calcium ion Ca²⁺ intae an oot o the cytoplasm functions as a signal for mony cellular processes. As a major material uised in mineralisation o bane, teeth an shells, calcium is the maist abundant metal bi mass in mony ainimals.

References

↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth–Heinemann. p. 112. ISBN 0080379419.
↑ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
↑ Krieck, Sven; Görls, Helmar; Westerhausen, Matthias (2010). "Mechanistic Elucidation of the Formation of the Inverse Ca(I) Sandwich Complex [(thf)3Ca(μ-C6H3-1,3,5-Ph3)Ca(thf)3] and Stability of Aryl-Substituted Phenylcalcium Complexes". Journal of the American Chemical Society. 132 (35): 12492–12501. doi:10.1021/ja105534w. PMID 20718434.
↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
↑ Dickson, A. G. and Goyet, C. (1994). "5". Handbook of method for the analysis of the various parameters of the carbon dioxide system in sea water, version 2 (PDF). ORNL/CDIAC-74. Archived frae the original (PDF) on 25 Mey 2011. Retrieved 29 Juin 2013.CS1 maint: multiple names: authors leet (link)

Freemit airtins

WebElements.com – Calcium
Calcium at The Periodic Cairt o Videos (Varsity o Nottingham)
USDA Naitional Nutrient Database, Calcium content o selectit fuids Archived 2004-10-31 at the Wayback Machine
UK Fuid Staundarts Agency: Calcium Archived 2010-10-07 at the Wayback Machine
Nutreetion fact sheet frae the Naitional Institutes o Health

[1] Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth–Heinemann. p. 112. ISBN 0080379419.

[CIAAW2013-2] Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.

[West-3] Krieck, Sven; Görls, Helmar; Westerhausen, Matthias (2010). "Mechanistic Elucidation of the Formation of the Inverse Ca(I) Sandwich Complex [(thf)3Ca(μ-C6H3-1,3,5-Ph3)Ca(thf)3] and Stability of Aryl-Substituted Phenylcalcium Complexes". Journal of the American Chemical Society. 132 (35): 12492–12501. doi:10.1021/ja105534w. PMID 20718434.

[4] Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.

[5] Dickson, A. G. and Goyet, C. (1994). "5". Handbook of method for the analysis of the various parameters of the carbon dioxide system in sea water, version 2 (PDF). ORNL/CDIAC-74. Archived frae the original (PDF) on 25 Mey 2011. Retrieved 29 Juin 2013.CS1 maint: multiple names: authors leet (link)

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