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Periodic Table of Elements

Element Calcium - Ca

Comprehensive data on the chemical element Calcium is provided on this page; including scores of properties, element names in many languages, most known nuclides of Calcium. Common chemical compounds are also provided for many elements. In addition technical terms are linked to their definitions and the menu contains links to related articles that are a great aid in one's studies.

Calcium Menu

• Calcium Page One
  • Overview of Calcium
  • Calcium's Name in Other Languages
  • Atomic Structure of Calcium
  • Chemical Properties of Calcium
  • Physical Properties of Calcium
  • Regulatory / Health
  • Who/When/Where/How
• Calcium Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides
• Calcium Page Three
  • Common Chemical Compounds of Calcium

Overview of Calcium

• Atomic Number: 20
• Group: 2
• Period: 4
• Series: Alkali Earth Metals

Calcium's Name in Other Languages

• Latin: Calcium
• Czech: Vápník
• Croatian: Kalcij
• French: Calcium
• German: Kalzium - r
• Italian: Calcio
• Norwegian: Kalsium
• Portuguese: Cálcio
• Russian: Кальций
• Spanish: Calcio
• Swedish: Kalcium

Atomic Structure of Calcium

• Atomic Radius: 2.23Å
• Atomic Volume: 29.9cm³/mol
• Covalent Radius: 1.74Å
• Cross Section (Thermal Neutron Capture)σ_a/barns: 0.43
• Crystal Structure: Cubic face centered

  

• Electron Configuration:

  1s² 2s²p⁶ 3s²p⁶ 4s²

• Electrons per Energy Level: 2,8,8,2

  Shell Model
  

• Ionic Radius: 0.99Å
• Filling Orbital: 4s²
• Number of Electrons (with no charge): 20
• Number of Neutrons (most common/stable nuclide): 20
• Number of Protons: 20
• Oxidation States: 2
• Valence Electrons: 4s²

  Electron Dot Model
  

Chemical Properties of Calcium

• Electrochemical Equivalent: 0.7477g/amp-hr
• Electron Work Function: 2.87eV
• Electronegativity: 1 (Pauling); 1.04 (Allrod Rochow)
• Heat of Fusion: 8.54kJ/mol
• Incompatibilities:

  water, oxidizers, acids, air, chlorine, chlorine tri-fluoride, fluorine, oxygen, silicon, sulfur

• Ionization Potential
  • First: 6.113
  • Second: 11.871
  • Third: 50.908
• Valence Electron Potential (-eV): 29

Physical Properties of Calcium

• Atomic Mass Average: 40.078
• Boiling Point: 1757K 1484°C 2703°F
• Coefficient of lineal thermal expansion/K^-1: 22E^-6
• Conductivity

  Electrical: 0.298 10⁶/cm Ω
  Thermal: 2.01 W/cmK

• Density: 1.55g/cc @ 300K
• Description:

  silvery, soft metal, tarnishes to grayish white after exposure to air.

• Elastic Modulus:
  • Bulk: 17/GPa
  • Rigidity: 7.4/GPa
  • Youngs: 20/GPa
• Enthalpy of Atomization: 184 kJ/mole @ 25°C
• Enthalpy of Fusion: 8.54 kJ/mole
• Enthalpy of Vaporization: 150 kJ/mole
• Flammablity Class: Flammable solid
• Freezing Point: see melting point
• Hardness Scale
  • Brinell: 167 MN m^-2
  • Mohs: 1.75
• Heat of Vaporization: 153.6kJ/mol
• Melting Point: 1112K 839°C 1542°F
• Molar Volume: 26.02 cm³/mole
• Physical State (at 20°C & 1atm): Solid
• Specific Heat: 0.632J/gK
• Vapor Pressure = 254Pa@839°C

Regulatory / Health

• CAS Number
  • 7440-70-2
• RTECS: EV8040000
• NFPA 704
  • Health: 1
  • Fire: 1
  • Reactivity: 2
  • Special Hazard:
• OSHA Permissible Exposure Limit (PEL)
  • No limits set by OSHA
• OSHA PEL Vacated 1989
  • No limits set by OSHA
• NIOSH Recommended Exposure Limit (REL)
  • No limits set by NIOSH
• Levels In Humans:
  Note: this data represents naturally occuring levels of elements in the typical human, it DOES NOT represent recommended daily allowances.
  • Blood/mg dm^-3: 60.5
  • Bone/p.p.m: 170000
  • Liver/p.p.m: 100-360
  • Muscle/p.p.m: 140-700
  • Daily Dietary Intake: 600-1400 mg
  • Total Mass In Avg. 70kg human: 1 kg

Who / Where / When / How

• Discoverer: Sir Humphrey Davy
• Discovery Location: London England
• Discovery Year: 1808
• Name Origin:

  Latin: calx, calcis (lime).

• Abundance of Calcium:
  • Earth's Crust/p.p.m.: 41000
  • Seawater/p.p.m.: 390
  • Atmosphere/p.p.m.: N/A
  • Sun (Relative to H=1E¹²): 2240000
• Sources of Calcium:

  Obtained from minerals like chalk, limestone & marble. Very abundant. Makes up 3.5% of crust. Occurs only in compounds. World production in 2000 was around 112,000,000 tons (CaO). Calcium is mined almost everywhere.

• Uses of Calcium:

  Used for dehydrating oils, decarburization and desulfurization of iron and its alloys, getter in vacuum tubes. Also used as an alloying agent for aluminum, copper and lead, a reducing agent for beryllium and used in fertilizer, concrete & plaster of paris. Calcium is an essential component shells, bones, teeth and plant structures.

• Additional Notes:

  Calcium was prepared as lime by the Romans under the name calyx in the 1st century A.D., but the metal was not discovered until 1808. Berzelius and Pontin prepared calcium amalgam by electrolizing lime in mercury. Davy was then successful in isolating the impure metal. Why did it take so long? Calcium is the fifth most abundant metalic element in the earth's crust, but is never found in the elemental form because it is so reactive. It is found in limestone (CaCO₃) gypsum (CaSO₄. 2H₂O) and fluorite (CaF₂). Pure calcium is a shiny soft metal that will react violently with water to produce hydrogen.

Calcium Menu

• Calcium Page One
  • Overview of Calcium
  • Calcium's Name in Other Languages
  • Atomic Structure of Calcium
  • Chemical Properties of Calcium
  • Physical Properties of Calcium
  • Regulatory / Health
  • Who/When/Where/How
• Calcium Page Two
  • Nuclides / Isotopes
  • Potential Parent Nuclides
• Calcium Page Three
  • Common Chemical Compounds of Calcium

References

A list of reference sources used to compile the data provided on our periodic table of elements can be found on the main periodic table page.

Related Resources

• Anatomy of the Atom
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• Molarity, Molality and Normality
  Introduces stoichiometry and explains the differences between molarity, molality and normality.
• Molar Mass Calculations and Javascript Calculator
  Molar mass calculations are explained and there is a JavaScript calculator to aid calculations.
• Chemical Database
  This database focuses on the most common chemical compounds used in the home and industry.

Citing this page

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Kenneth Barbalace. Periodic Table of Elements - Calcium - Ca. EnvironmentalChemistry.com. 1995 - 2025. Accessed on-line: 12/16/2025
https://EnvironmentalChemistry.com/yogi/periodic/Ca.html/Ca-compounds.html
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