Template:Infobox calcium

potassium ← calcium → scandium Mg ↑ Ca ↓ Sr 20Ca Periodic table
Appearance
Dull gray, silver Spectral lines of Calcium
General properties
Name, symbol, number	calcium, Ca, 20
Pronunciation	/ˈkælsiəm/ kal-see-əm
Element category	alkaline earth metal
Group, period, block	2, 4, s
Standard atomic weight	40.078(4)
Electron configuration	[Ar] 4s2
Electrons per shell	2, 8, 8, 2 (Image)
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, +1 (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
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
Most stable isotopes
Main article: Isotopes of 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 β−β−  ? 46Ti 47Ca syn 4.536 d β− 0.694, 1.99 47Sc γ 1.297 - 48Ca 0.187% >4×1019 y β−β−  ? 48Ti

References

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