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Calcium [Ca] – Element Details, History, Atomic Structure, Facts, Properties, Electronic Configuration, Atomic Spectrum, Uses.


Element 20 of Periodic table is Calcium with atomic number 20, atomic weight 40.078. Calcium, symbol Ca, has a Face Centered Cubic structure and Silver color. Calcium is a Alkaline Earth Metal element. It is part of group 2 (beryllium family). Know everything about Calcium Facts, Physical Properties, Chemical Properties, Electronic configuration, Atomic and Crystal Structure.

History of Calcium

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’.

Davy discovered the metal by electrolysis of quicklime.

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 Facts

Atomic Symbol
Atomic Number
Atomic Weight
Alkaline Earth Metal
Group in Periodic Table
Group Name
Beryllium family
Block in Periodic Table
s -block
Period in Periodic Table
Electronic Configuration
[Ar] 4s2
Melting Point
1115 K
Boiling Point
1757 K
Electronic Shell Structure
2, 8, 8, 2
CAS Number

Calcium Atomic Structure 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

Element Properties

Atomic Number
Number of Protons
Mass Number
Number of Neutrons
Shell structure (Electrons per energy level)
[2, 8, 8, 2]
Electron Configuration
[Ar] 4s2
Valence Electrons
Oxidation State
Atomic Term Symbol (Quantum Numbers)

Atomic Structure of Calcium

Atomic Radius
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
Neutron Mass Absorption

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.

Regulatory and Health - Health and Safety Parameters and Guidelines

DOT Hazard Class
DOT Numbers
NFPA Fire Rating
NFPA Hazards
Water Reactive
Autoignition Point
NFPA Health Rating

Physical Properties

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
Shear Modulus
7.4 GPa
Bulk Modulus
17 GPa
Poisson Ratio

Electrical Properties

Electrical Conductivity
29000000 S/m
3.4e-8 m Ω
Superconducting Point

Magnetic Properties

Magnetic Type
Curie Point
Mass Magnetic Susceptibility
1.38e-8 m3/kg
Molar Magnetic Susceptibility
5.531e-10 m3/mol
Volume Magnetic Susceptibility

Thermal Properties

Melting Point
1115 K (841.85°C, 1547.3300000000002 °F)
Boiling Point
1757 K (1483.85°C, 2702.93 °F)
Critical Temperature
Superconducting Point

Use of Calcium

Human needs calcium for muscles to move and for nerves to carry messages between your brain and every part of your body. Calcium also helps blood vessels move blood throughout your body and helps release hormones that affect many functions in your body. Vitamin D helps your body absorb calcium.

106. Seaborgium [Sg]