Calcium

chemical element wi the atomic nummer o 20

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, 20Ca
Template:Infobox element/symbol-to-top-image/alt
Calcium
Appearancedull gray, siller; wi a pale yellae tint[1]
Standard atomic weight Ar, std(Ca)40.078(4)[2]
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
Blocks-block
Element category  Alkaline yird metal
Electron confeeguration[Ar] 4s2
Electrons per shell2, 8, 8, 2
Pheesical properties
Phase at STPsolit
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+1,[3] +2 strangly basic
ElectronegativityPauling scale: 1.00
Ionisation energies
  • 1st: 589.8 kJ/mol
  • 2nd: 1145.4 kJ/mol
  • 3rd: 4912.4 kJ/mol
  • (more)
Atomic radiusempirical: 197 pm
Covalent radius176±10 pm
Van der Waals radius231 pm
Colour lines in a spectral range
Spectral lines o calcium
Ither properties
Naitural occurrenceprimordial
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 rod3810 m/s (at 20 °C)
Thermal expansion22.3 µm/(m·K) (at 25 °C)
Thermal conductivity201 W/(m·K)
Electrical resistivity33.6 nΩ·m (at 20 °C)
Magnetic orderindiamagnetic
Magnetic susceptibility+40.0·10−6 cm3/mol[4]
Young's modulus20 GPa
Shear modulus7.4 GPa
Bulk modulus17 GPa
Poisson ratio0.31
Mohs haurdness1.75
Brinell haurdness170–416 MPa
CAS Nummer7440-70-2
History
Diskivery an first isolationHumphry Davy (1808)
Main isotopes o calcium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
40Ca 96.941% stable
41Ca trace 9.94×104 y ε 41K
42Ca 0.647% stable
43Ca 0.135% stable
44Ca 2.086% stable
45Ca syn 162.6 d β 45Sc
46Ca 0.004% stable
47Ca syn 4.5 d β 47Sc
γ
48Ca 0.187% 6.4×1019 y ββ 48Ti
| references

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.

ReferencesEedit

  1. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth–Heinemann. p. 112. ISBN 0080379419.
  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.
  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.CS1 maint: multiple names: authors leet (link)

Freemit airtinsEedit