Calcium

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Calcium,  20Ca
Calcium unter Argon Schutzgasatmosphäre.jpg
General properties
Appearancedull gray, siller
Staundart atomic wecht (Ar, staundart)40.078(4)[1]
Calcium in the periodic cairt
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gowd Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium
Mg

Ca

Sr
potassiumcalciumscandium
Atomic nummer (Z)20
Groupgroup 2 (alkaline yird metals)
Periodperiod 4
Element category  alkalineearthmetal
Blocks-block
Electron confeeguration[Ar] 4s2
Electrons per shell
2, 8, 8, 2
Pheesical properties
Phase (at STP)solit
Meltin pynt1115 K ​(842 °C, ​1548 °F)
Bylin pynt1757 K ​(1484 °C, ​2703 °F)
Density (near r.t.)1.55 g/cm3
when liquid (at m.p.)1.378 g/cm3
Heat o fusion8.54 kJ/mol
Heat o vapourisation154.7 kJ/mol
Molar heat capacity25.929 J/(mol·K)
Vapour pressur
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 864 956 1071 1227 1443 1755
Atomic properties
Oxidation states+2, +1[2] ​strongly basic oxide
ElectronegativityPauling scale: 1.00
Ionisation energies
Atomic radiusempirical: 197 pm
Covalent radius176±10 pm
Van der Waals radius231 pm
Coloyr lines in a spectral range
Spectral lines o Calcium
Miscellanea
Creestal structurface-centred cubic (fcc)
Face-centered cubic creestal structur for calcium
Speed o soond thin rod3810 m/s (at 20 °C)
Thermal expansion22.3 µm/(m·K) (at 25 °C)
Thermal conductivity201 W/(m·K)
Electrical resistivity33.6 n Ω·m (at 20 °C)
Magnetic orderindiamagnetic
Young's modulus20 GPa
Shear modulus7.4 GPa
Bouk modulus17 GPa
Poisson ratio0.31
Mohs haurdness1.75
Brinell haurdness167 MPa
CAS Nummer7440-70-2
History
DiskiveryHumphry Davy (1808)
First isolationHumphry Davy (1808)
Main isotopes o calcium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
40Ca 96.941% >5.9×1021 y β+β+ 40Ar
41Ca trace 1.03×105 y ε 41K
42Ca 0.647% stable
43Ca 0.135% stable
44Ca 2.086% stable
45Ca syn 162.7 d β 45Sc
46Ca 0.004% >2.8×1015 y ββ 46Ti
47Ca syn 4.536 d β 47Sc
γ -
48Ca 0.187% 4.3×1019 y ββ 48Ti
β
(nae observed)
48Sc
| references | in Wikidata

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.[3]

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[eedit | eedit soorce]

  1. Meija, J.; 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. 
  2. 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): 100818110534020. doi:10.1021/ja105534w. PMID 20718434. 
  3. 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. 

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