Calcium

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Calcium
20Ca
Mg

Ca

Sr
potassiumcalciumscandium
Ìhànsójú
Dull gray, silver
Àwọn ìdámọ́ wíwọ́pọ̀
Orúkọ, àmì-ìdámọ́, nọ́mbà calcium, Ca, 20
Ẹ̀ka ẹ́límẹ̀nti alkaline earth metal
Ẹgbẹ́, àsìkò, àdìpò 24, s
Ìwúwo átọ́mù 40.078(4)
Ìtòléra ẹ̀lẹ́ktrónì [Ar] 4s2
2, 8, 8, 2
Physical properties
Phase solid
Density (near r.t.) 1.55 g·cm−3
Liquid density at m.p. 1.378 g·cm−3
Melting point 1115 K, 842 °C, 1548 °F
Boiling point 1757 K, 1484 °C, 2703 °F
Heat of fusion 8.54 kJ·mol−1
Heat of vaporization 154.7 kJ·mol−1
Molar heat capacity 25.929 J·mol−1·K−1
Vapor pressure
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
(strongly basic oxide)
Electronegativity 1.00 (Pauling scale)
Ionization energies
(more)
1st: 589.8 kJ·mol−1
2nd: 1145.4 kJ·mol−1
3rd: 4912.4 kJ·mol−1
Atomic radius 197 pm
Covalent radius 176±10 pm
Van der Waals radius 231 pm
Miscellanea
Crystal structure face-centered cubic
Calcium has a face-centered cubic crystal structure
Magnetic ordering diamagnetic
Electrical resistivity (20 °C) 33.6 nΩ·m
Thermal conductivity 201 W·m−1·K−1
Thermal expansion (25 °C) 22.3 µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 3810 m·s−1
Young's modulus 20 GPa
Shear modulus 7.4 GPa
Bulk modulus 17 GPa
Poisson ratio 0.31
Mohs hardness 1.75
Brinell hardness 167 MPa
CAS registry number 7440-70-2
Àwọn ísótòpù dídúró jùlọ
Main article: Àwọn ísótòpù calcium
iso NA half-life DM DE (MeV) DP
40Ca 96.941% 40Ca is stable with 20 neutrons
41Ca trace 1.03×105 y ε - 41K
42Ca 0.647% 42Ca is stable with 22 neutrons
43Ca 0.135% 43Ca is stable with 23 neutrons
44Ca 2.086% 44Ca is stable with 24 neutrons
45Ca syn 162.7 d β 0.258 45Sc
46Ca 0.004% >2.8×1015 y ββ  ? 46Ti
47Ca syn 4.536 d β 0.694, 1.99 47Sc
γ 1.297 -
48Ca 0.187% >4×1019 y ββ  ? 48Ti
· r

Kalsiomu ni elimenti kemika pelu ami-idamo Ca ati nomba atomu 20. Kalsiomu je metali alkalini inu-ile alawo oju-orun dide lowo, fifth-most-abundant element by mass in the Earth's crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.[1] Free calcium metal is too reactive to occur in nature. Calcium is produced in the explosions at the end of the life of massive stars

Calcium is essential for living organisms, in particular in cell physiology, where movement of the calcium ion into and out of the cytoplasm functions as a signal for many cellular processes. As a major material used in mineralization of bone, teeth and shells, calcium is the most abundant metal by mass in many animals.


Itokasi[àtúnṣe | àtúnṣe àmìọ̀rọ̀]

  1. Dickson, A. G.; Goyet, C. (1994). "Chapter 5". Handbook of method for the analysis of the various parameters of the carbon dioxide system in sea water, version 2. ORNL/CDIAC-74. http://cdiac.esd.ornl.gov/ftp/cdiac74/chapter5.pdf.