Sesium chemiese eienskappe (25 feite wat jy moet weet)

Caesium(Cs) element also written as Cesium is a chemical element that belongs to the group 1st. Let us study some facts about Caesium.

Caesium(Cs) is an alkali metal element that belongs to the hydrogen family in the periodic table. It is having atomic number 55 u and a mass is 132.9 g/mol. 

Let us discuss some more chemical properties like melting point, boiling point, ionization energy, and oxidation state in detail below.

Caesium symbol

A code is used to distinguish one element from another in the Periodic Table of Elements. Let us check the atomic symbol of Caesium.

Caesium(Cs) is represented with the symbol Cs in the periodic table.

Caesium group in periodic table

In the periodic table, a group is a column of elements. Let us check the Group of Caesium belongs.

In the periodic table Caesium(Cs) lie in group 1.

Caesium period in periodic table

In the periodic table, a period is a row of elements. Let us check to which period Caesium belongs.

Caesium(Cs) elements lie in the 6th period of the modern periodic table.

Caesium block in periodic table

Block is a generic term for a collection of elements from the periodic table. Let us check from which block the caesium lie.

Caesium(Cs) element belongs to the s-block (Alkali metal group) of the periodic table.

Caesium atomic number

A nucleus’ atomic number is defined as its number of protons or electrons. Let us check the atomic number of Caesium.

The atomic number(Z) of the caesium(Cs) atom is Z = 55.

Caesium atomic Weight

The atomic weight is the ratio of a chemical element’s atoms’ average mass to a reference value. Let us check the atomic weight of Caesium.

The atomic weight of the caesium(Cs) is 132.9 g/mol.

Caesium electronegativity according to Pauling

Electronegativity means the measurement of an atom’s ability to attract a pair of bonding electrons. Let us check the value of electronegativity of Caesium.

Pauling scale determined that caesium had an electronegativity of 0.79. Despite being a reactive metal, it is thought to be the least electronegative element.

Caesium atomic Density

A measure is the number of atoms or nuclides per cubic centimetre (cm3) or per barn-cm. Let us find out the atomic density of Caesium.

The atomic density of the caesium element is 1.873 g/cm3.

Caesium melting point

The temperature at which a substance transforms from a solid to a liquid. Let us check the melting point of Caesium.

The melting point of Caesium(Cs) is 28.5 °C (83.3 °F)  because of this melting point it is one of just five elemental metals with a liquid state at or close to room temperature. 

Caesium boiling point

The saturation pressure is the point at which boiling begins to happen for a specific temperature. Let us find the boiling point of Caesium.

The boiling point of Caesium(Cs) is 671 °C(​1240 °F) at 944 K. 

Caesium vanderwaals radius

The radius of a hypothetical hard sphere representing the separation between two atoms is known as the van der Waals radius. Let us find out the radius of the caesium.

The vanderwaals radius of caesium is 343 pm(1*10-12m).

Caesium ionic radius

The diameter of an atom’s ion within a crystal lattice is known as the ionic radius. Let us check the ionic radius of Caesium.

The ionic radius of caesium is 1.74 Å in case of its +1 charge on it. Ionic radius is different from atomic radius because it works on ions.

Caesium isotopes

Isotopes are substances with uniformly distributed protons but variable quantities of neutrons. Let us find out the isotopes of caesium.

Caesium has 40 isotopes and the maximum number of isotopic elements. The list of most common isotopes of caesium is given below:

  1. 133Cs
  2. 134Cs
  3. 135Cs 
  4. 136Cs
  5. 137Cs 


The most stable caesium isotope is caesium-133. A unique caesium-133 transition determines the second as the SI base unit of time.


When Caesium-134 decays, it immediately produces 134Ba and emits, on average, 2.23 gamma-ray photons.


Caesium-135 is a weakly radioactive isotope of calcium with a ½ of 2.3 million years. It decays by emitting a low-energy beta photon into the stable isotope barium-135 instead.


The production of caesium-136 does not occur from other fission product nuclides of mass 136.


One of the two main medium-lived fission products is caesium-137, which has a half-life of 30.17 years.

Caesium electronic shell

Areas surrounding the atomic nucleus with a specified number of electrons are known as the electron shell. Let us find out the electronic shell of caesium.

The electronic shell of the caesium consists of 2,8,18,18,8,1. This shell determined the electronic configuration of Cs.

Caesium energy of first ionisation

In one mole of neutral gaseous atoms, one mole of gaseous ions will be formed if the loosest electron is removed. Let us check the First ionisation energy of Caesium.

Caesium’s first ionisation energy is 3.8939 eV or 375.7 kJ/mol. 

Caesium energy of second ionisation

The forces necessary to free the outermost, or least bound, electron from an element’s 1+ ion. Let us find the second ionisation energy of Caesium.

Caesium’s second ionisation energy is 23.15 eV or 2234.3 kJ/mol.

Caesium energy of third ionisation

Known as the third ionization energy, it is necessary to expel an electron from a 2+ ion. Let us find out the third ionisation energy of Caesium.

Caesium’s Third ionisation energy is 35.2376 eV or 3400 kJ/mol.

Caesium oxidation states

The potential charge an atom would have if all of its links to other atoms were ionic. Let us check the oxidation state of Caesium.

Caesium has oxidation numbers of +1 and -1, with +1 being the most stable.

Caesium electron configurations

Electron configuration describes how electrons are distributed in an element’s atomic orbitals. Let us check the electronic configuration of Caesium.

The entire electron configuration of cesium will be 1s2, 2's2, 2p6, 3's2, 3p6,3d10,4s2, 4p6,4d10,5s2, 5p6, en 6s1 or we can also write it as [Xe ]6s1.

Caesium CAS number

The U.S. Chemical Abstracts Service(U.CAS) assigns chemical substances a numerical identification known as a CAS number. Let us check the CAS number of Caesium.

The CAS number of Caesium is 7440-46-2.

Caesium ChemSpider ID

ChemSpider ID is a database with information on chemicals. Let us check the ChemSpider ID of caesium.

The chemSpider ID of  caesium is 4510778.

Caesium allotropic forms

Chemical elements can exist in two or more distinct forms while still maintaining the same physical state. Let us check how many allotropes of Caesium have.

Caesium does not have any allotropic forms present in nature.

Caesium chemical classification

Introduces the fundamentals of classification and lists resources for in-depth assistance and guidance. Let us check some chemical properties of Caesium.

Caesium has many chemical properties and reactions as listed below:

  1. Caesium and water react quickly. It forms an alkaline solution when it reacts with water, which is a distinctive property shared by all of the group 1 elements.
  2. Salts of caesium are created when caesium combines with weak acids.
  3. The substance of Cs is regarded as the periodic table’s most electropositive.

Caesium state at room temperature

The temperature of a room is measured by a thermometer. Let us check the temperature of the Caesium.

At room temperature, Caesium is a solid because of its metallic behaviour. But as the temperature is slightly increased from room temperature it melts into a liquid and reacts violently with cold water. 

Is caesium paramagnetic?

Unpaired electrons present in the electronic configuration define the paramagnetic character. Let us check whether Caesium is paramagnetic or not.

Caesium is paramagnetic with different values of magnetic susceptibility listed below:

waarde van
2.8 * 10-9 m3/ kg
5.26 * 10-6
3.72 * 10-10 m3/mol
paramagneties Value of Cs


A silvery-gold metal, caesium. It has a warm tone but is not as yellow as high-karat gold. The metal will have to change from its solid state into liquid. Gallium, francium, and caesium are the other three metals that are more liquefiable at or near room temperature than mercury.

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