Calcium Element Information, Facts, Properties, Trends, Uses, Comparison with other elements
Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray Alkaline Earth Metal, 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.
It belongs to group 2 of the periodic table having trivial name alkaline earth metals*. You can also download Printable Periodic Table of Elements Flashcards for Calcium in a PDF format.
Calcium Facts
Read key information and facts about element Calcium
| Name | Calcium |
| Atomic Number | 20 |
| Atomic Symbol | Ca |
| Atomic Weight | 40.078 |
| Phase | Solid |
| Color | Silver |
| Appearance | - |
| Classification | Alkaline Earth Metal |
| Natural Occurance | Primordial |
| Group in Periodic Table | 2 |
| Group Name | beryllium family |
| Period in Periodic Table | period 4 |
| Block in Periodic Table | s-block |
| Electronic Configuration | [Ar] 4s2 |
| Electronic Shell Structure (Electrons per shell) | 2, 8, 8, 2 |
| Melting Point | 1115 K |
| Boiling Point | 1757 K |
| CAS Number | CAS7440-70-2 |
How to Locate Calcium on Periodic Table
Periodic table is arranged by atomic number, number of protons in the nucleus which is same as number of electrons. The atomic number increases from left to right. Periodic table starts at top left ( Atomic number 1) and ends at bottom right (atomic number 118). Therefore you can directly look for atomic number 20 to find Calcium on periodic table.
Another way to read periodic table and locate an element is by using group number (column) and period number (row). To locate Calcium on periodic table look for cross section of group 2 and period 4 in the modern periodic table.
Calcium History
The element Calcium was discovered by H. Davy in year 1808 in United Kingdom. Calcium was first isolated by H. Davy in 1808. Calcium derived its name from the Latin calx, meaning 'lime'.
| Discovered By | H. Davy |
| Discovery Date | 1808 in United Kingdom |
| First Isolation | 1808 |
| Isolated by | H. Davy |
Davy discovered the metal by electrolysis of quicklime.
Calcium Uses
Calcium is used to prepare thorium and uranium as reducing agents. It is also used as an alloying agent in aluminum, copper, lead, and magnesium.
Calcium Presence: Abundance in Nature and Around Us
The table below shows the abundance of Calcium in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.
| ppb by weight (1ppb =10^-7 %) | ppb by atoms (1ppb =10^-7 %) | |
|---|---|---|
| Abundance in Universe | 70000 | 2000 |
| Abundance in Sun | 70000 | 2000 |
| Abundance in Meteorites | 11000000 | 5200000 |
| Abundance in Earth's Crust | 50000000 | 26000000 |
| Abundance in Oceans | 4220 | 650 |
| Abundance in Humans | 14000000 | 2200000 |
Crystal Structure of Calcium
The solid state structure of Calcium is Face Centered Cubic.
The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.
Unit Cell Parameters
The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)
| a | b | c |
|---|---|---|
| 558.84 pm | 558.84 pm | 558.84 pm |
and the angles between them Lattice Angles (alpha, beta and gamma).
| alpha | beta | gamma |
|---|---|---|
| π/2 | π/2 | π/2 |
The positions of the atoms inside the unit cell are described by the set of atomic positions ( xi, yi, zi) measured from a reference lattice point.
The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.
| Space Group Name | Fm_ 3m |
| Space Group Number | 225 |
| Crystal Structure | Face Centered Cubic |
| Number of atoms per unit cell | 4 |
The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic are 1,4,2 respectively.
Calcium Atomic and Orbital Properties
Calcium atoms have 20 electrons and the electronic shell structure is [2, 8, 8, 2] with Atomic Term Symbol (Quantum Numbers) 1S0.
| Atomic Number | 20 |
| Number of Electrons (with no charge) | 20 |
| Number of Protons | 20 |
| Mass Number | 40 |
| Number of Neutrons | 20 |
| Shell structure (Electrons per energy level) | 2, 8, 8, 2 |
| Electron Configuration | [Ar] 4s2 |
| Valence Electrons | 4s2 |
| Valence (Valency) | 2 |
| Main Oxidation States | 2 |
| Oxidation States | 1, 2 |
| Atomic Term Symbol (Quantum Numbers) | 1S0 |
Bohr Atomic Model of Calcium - Electrons per energy level
| n | s | p | d | f |
|---|
Ground State Electronic Configuration of Calcium - neutral Calcium atom
Abbreviated electronic configuration of Calcium
The ground state abbreviated electronic configuration of Neutral Calcium atom is [Ar] 4s2. The portion of Calcium configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Ar]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. This is important as it is the Valence electrons 4s2, electrons in the outermost shell that determine the chemical properties of the element.
Unabbreviated electronic configuration of neutral Calcium
Complete ground state electronic configuration for the Calcium atom, Unabbreviated electronic configuration
1s2 2s2 2p6 3s2 3p6 4s2
Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.
As per the Aufbau principle the electrons will occupy the orbitals having lower energies before occupying higher energy orbitals. According to this principle, electrons are filled in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…
The Pauli exclusion principle states that a maximum of two electrons, each having opposite spins, can fit in an orbital.
Hund's rule states that every orbital in a given subshell is singly occupied by electrons before a second electron is filled in an orbital.
Atomic Structure of Calcium
Calcium atomic radius is 194 pm, while it's covalent radius is 174 pm.
| Atomic Radius Calculated | 194 pm(1.94 Å) |
| Atomic Radius Empirical | 180 pm (1.8 Å) |
| Atomic Volume | 25.857 cm3/mol |
| Covalent Radius | 174 pm (1.74 Å) |
| Van der Waals Radius | 231 pm |
| Neutron Cross Section | 0.43 |
| Neutron Mass Absorption | 0.00037 |
Spectral Lines of Calcium - Atomic Spectrum of Calcium
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.
Spectral lines are the result of interaction between a quantum system and a single photon. A spectral line may be observed either as an emission line or an absorption line.
Spectral lines are highly atom-specific, and can be used to identify the chemical composition of any medium. Several elements, including helium, thallium, and caesium, were discovered by spectroscopic means. They are widely used to determine the physical conditions of stars and other celestial bodies that cannot be analyzed by other means.
Emission spectrum of Calcium
Absorption spectrum of Calcium
Calcium Chemical Properties: Calcium Ionization Energies and electron affinity
The electron affinity of Calcium is 2.37 kJ/mol.
| Valence | 2 |
| Electronegativity | 1 |
| ElectronAffinity | 2.37 kJ/mol |
Ionization Energy of Calcium
Ionization energy is the amount of energy required to remove an electron from an atom or molecule.in chemistry, this energy is expresed in kilocalories per mole (kcal/mol) or kilojoules per mole (kJ/mol).
Refer to table below for Ionization energies of Calcium
| Ionization energy number | Enthalpy - kJ/mol |
|---|---|
| 1st | 589.8 |
| 2nd | 1145.4 |
| 3rd | 4912.4 |
| 4th | 6491 |
| 5th | 8153 |
| 6th | 10496 |
| 7th | 12270 |
| 8th | 14206 |
| 9th | 18191 |
| 10th | 20385 |
| 11th | 57110 |
| 12th | 63410 |
| 13th | 70110 |
| 14th | 78890 |
| 15th | 86310 |
| 16th | 94000 |
| 17th | 104900 |
| 18th | 111711 |
| 19th | 494850 |
| 20th | 527762 |
Calcium Physical Properties
Refer to below table for Calcium Physical Properties
| Density | 1.55 g/cm3(when liquid at m.p density is $1.378 g/cm3) |
| Molar Volume | 25.857 cm3/mol |
Elastic Properties
| Young Modulus | 20 |
| Shear Modulus | 7.4 GPa |
| Bulk Modulus | 17 GPa |
| Poisson Ratio | 0.31 |
Hardness of Calcium - Tests to Measure of Hardness of Element
| Mohs Hardness | 1.75 MPa |
| Vickers Hardness | - |
| Brinell Hardness | 167 MPa |
Calcium Electrical Properties
Electrical resistivity measures element's electrical resistance or how strongly it resists electric current.The SI unit of electrical resistivity is the ohm-metre (Ω⋅m). While Electrical conductivity is the reciprocal of electrical resistivity. It represents a element's ability to conduct electric current. The SI unit of electrical conductivity is siemens per metre (S/m).
Calcium is a conductor of electricity. Refer to table below for the Electrical properties of Calcium
| Electrical conductors | Conductor |
| Electrical Conductivity | 29000000 S/m |
| Resistivity | 3.4e-8 m Ω |
| Superconducting Point | - |
Calcium Heat and Conduction Properties
| Thermal Conductivity | 200 W/(m K) |
| Thermal Expansion | 0.0000223 /K |
Calcium Magnetic Properties
| Magnetic Type | Paramagnetic |
| Curie Point | - |
| Mass Magnetic Susceptibility | 1.38e-8 m3/kg |
| Molar Magnetic Susceptibility | 5.531e-10 m3/mol |
| Volume Magnetic Susceptibility | 0.00002139 |
Optical Properties of Calcium
| Refractive Index | - |
Acoustic Properties of Calcium
| Speed of Sound | 3810 m/s |
Calcium Thermal Properties - Enthalpies and thermodynamics
Refer to table below for Thermal properties of Calcium
| Melting Point | 1115 K(841.85 °C, 1547.330 °F) |
| Boiling Point | 1757 K(1483.85 °C, 2702.930 °F) |
| Critical Temperature | - |
| Superconducting Point | - |
Enthalpies of Calcium
| Heat of Fusion | 8.54 kJ/mol |
| Heat of Vaporization | 155 kJ/mol |
| Heat of Combustion | -990 J/(kg K) |
Calcium Isotopes - Nuclear Properties of Calcium
Calcium has 24 isotopes, with between 34 and 57 nucleons. Calcium has 5 stable naturally occuring isotopes.
Isotopes of Calcium - Naturally occurring stable Isotopes: 40Ca, 42Ca, 43Ca, 44Ca, 46Ca.
| Isotope | Z | N | Isotope Mass | % Abundance | T half | Decay Mode |
|---|---|---|---|---|---|---|
| 34Ca | 20 | 14 | 34 | Synthetic | ||
| 35Ca | 20 | 15 | 35 | Synthetic | ||
| 36Ca | 20 | 16 | 36 | Synthetic | ||
| 37Ca | 20 | 17 | 37 | Synthetic | ||
| 38Ca | 20 | 18 | 38 | Synthetic | ||
| 39Ca | 20 | 19 | 39 | Synthetic | ||
| 40Ca | 20 | 20 | 40 | 96.941% | Stable | |
| 41Ca | 20 | 21 | 41 | Synthetic | ||
| 42Ca | 20 | 22 | 42 | 0.647% | Stable | N/A |
| 43Ca | 20 | 23 | 43 | 0.135% | Stable | N/A |
| 44Ca | 20 | 24 | 44 | 2.086% | Stable | N/A |
| 45Ca | 20 | 25 | 45 | Synthetic | ||
| 46Ca | 20 | 26 | 46 | 0.004% | Stable | N/A |
| 47Ca | 20 | 27 | 47 | Synthetic | ||
| 48Ca | 20 | 28 | 48 | 0.187% | Stable | N/A |
| 49Ca | 20 | 29 | 49 | Synthetic | ||
| 50Ca | 20 | 30 | 50 | Synthetic | ||
| 51Ca | 20 | 31 | 51 | Synthetic | ||
| 52Ca | 20 | 32 | 52 | Synthetic | ||
| 53Ca | 20 | 33 | 53 | Synthetic | ||
| 54Ca | 20 | 34 | 54 | Synthetic | ||
| 55Ca | 20 | 35 | 55 | Synthetic | ||
| 56Ca | 20 | 36 | 56 | Synthetic | ||
| 57Ca | 20 | 37 | 57 | Synthetic |
Regulatory and Health - Health and Safety Parameters and Guidelines
The United States Department of Transportation (DOT) identifies hazard class of all dangerous elements/goods/commodities either by its class (or division) number or name. The DOT has divided these materials into nine different categories, known as Hazard Classes.
| DOT Numbers | 1855 |
| DOT Hazard Class | 4.2 |
NFPA 704 is a Standard System for the Identification of the Hazards of Materials for Emergency Response. NFPA is a standard maintained by the US based National Fire Protection Association.
The health (blue), flammability (red), and reactivity (yellow) rating all use a numbering scale ranging from 0 to 4. A value of zero means that the element poses no hazard; a rating of four indicates extreme danger.
| NFPA Fire Rating | 1 | Flash Points Above 93.3°C (200°F) |
| NFPA Health Rating | 3 | Flash Points below 37.8°C (100°F) |
| NFPA Reactivity Rating | 2 | Flash Points Above 37.8°C (100°F) not exceeding 93.3°C (200°F) |
| NFPA Hazards | Water Reactive |
| Autoignition Point | - |
| Flashpoint | - |
Database Search
List of unique identifiers to search the element in various chemical registry databases
| Database | Identifier number |
|---|---|
| CAS Number - Chemical Abstracts Service (CAS) | CAS7440-70-2 |
| RTECS Number | - |
| CID Number | CID5460341 |
| Gmelin Number | - |
| NSC Number | - |
Compare Calcium with other elements
Compare Calcium with Group 2, Period 4 and Alkaline Earth Metal elements of the periodic table.
Compare Calcium with all Group 2 elements
Compare Calcium with all Period 4 elements
Compare Calcium with all Alkaline Earth Metal elements
Frequently Asked Questions (FAQ)
Find the answers to the most frequently asked questions about Calcium