Cesium (Cs) – Periodic Table [Element Information & More]

cesium element periodic table

Cesium element (Cs) is in group 1 and period 6 of a periodic table. Cesium is in the s-block and it is classified as an alkali metal on the periodic table.

There is a lot more information related to cesium which is mentioned in the Information Table given below.

So let’s dive right into it!

Table of contents

Cesium Element (Information Table)

The important data related to cesium element is given in the table below.

Appearance of cesiumSilvery pale golden appearance
Atomic number of cesium55
Symbol of cesiumCs
Atomic mass of cesium132.91 u
Protons, Neutrons & Electrons in cesiumProtons: 55, Neutrons: 78, Electrons: 55
State of cesium (at STP)Solid
Group number of cesium in periodic table1
Period number of cesium in periodic table6
Block of cesium in periodic tables-block
Category of cesiumAlkali metal
Bohr model or Electrons per shell or Electrons arrangement in cesium2, 8, 18, 18, 8, 1
Electron configuration of cesium[Xe] 6s1
Orbital diagram of cesiumorbital diagram of cesium
Valence electron in cesium1
Electronegativity of cesium (on pauling scale)0.79
Atomic radius of cesium (van der Waals radius)343 picometers
Density of cesium1.88 g/cm3
1st ionization energy of cesium3.894 eV
Main isotope of cesium133Cs
Melting point of cesium301.7 K or 28.5 °C or 83.3 °F
Boiling point of cesium944 K or 671 °C or 1240 °F
Crystal structure of cesiumBody Centered Cubic (BCC)
Discovery of cesiumBy Gustav Kirchhoff and Robert Bunsen (in 1860)

Also see: Interactive Periodic Table (It has rotating bohr models as well as many other details of all the 118 elements in a single periodic table).

Cesium element in Periodic table

The Cesium element (Cs) has the atomic number 55 and is located in group 1 and period 6. Cesium is in solid state at STP and it is classified as an alkali metal on the periodic table.

Click on above elements in the periodic table to see their information.

Facts about cesium

Here are a few interesting facts about cesium.

  1. Cesium was given its name from the Latin word “caesius”, meaning sky blue.
  2. Cesium is the 50th most abundant element present in the earth’s crust.
  3. The concentration of cesium in the earth’s crust is around 3 ppm by weight.
  4. Bernic lake (in Canada) has the largest deposits of Pollucite (which is an ore of cesium).
  5. The density of cesium metal is twice the density of water.

Properties of cesium

Here is a list of some physical properties and chemical properties of cesium.

Physical properties of cesium

  • Cesium has a silvery pale golden appearance.
  • Cesium is ductile and it can be drawn into thin wires.
  • Cesium is a very soft metal (just like a wax). Cesium can be cut with a kitchen knife.
  • The melting point and boiling point of cesium are 28.5 °C and 671 °C respectively.
  • There are many isotopes of cesium and the most abundant isotope is 133Cs.
  • Cesium has FCC crystal structure.

Chemical properties of cesium

  • Cesium is a very reactive alkali metal and because of this it is always found in compounds with other elements.
  • Cesium has 1 valence electron and this electron is lost during a chemical reaction to gain stability.
  • Cesium is highly reactive and it is always kept in kerosene or mineral oil to prevent its reaction with air.
  • Cesium reacts violently with water and forms cesium hydroxide.

Uses of cesium

Here are some uses of the cesium element.

  • Cesium is used in the hydrogenation of organic compounds.
  • Cesium is also used in vacuum tubes to remove oxygen gas.
  • Some compounds of cesium are also used in the manufacturing of optical glasses.
  • Cesium is used in photomultiplier tubes as well as photoelectric cells.

External resources:

  1. P. (n.d.). Cesium | Cs (Element) – PubChem. Cesium | Cs (Element) – PubChem. https://pubchem.ncbi.nlm.nih.gov/element/Cesium
  2. It’s Elemental – The Element Cesium. (n.d.). It’s Elemental – the Element Cesium. https://education.jlab.org/itselemental/ele055.html
  3. Caesium – Wikipedia. (2010, September 26). Caesium – Wikipedia. https://en.wikipedia.org/wiki/Caesium
  4. Cesium and Rubidium Statistics and Information | U.S. Geological Survey. (n.d.). Cesium and Rubidium Statistics and Information | U.S. Geological Survey. https://www.usgs.gov/centers/national-minerals-information-center/cesium-and-rubidium-statistics-and-information
  5. Atomic Data for Cesium (Cs). (n.d.). Atomic Data for Cesium (Cs). https://physics.nist.gov/PhysRefData/Handbook/Tables/cesiumtable1.htm
  6. Caesium – Element information, properties and uses | Periodic Table. (n.d.). Caesium – Element Information, Properties and Uses | Periodic Table. https://www.rsc.org/periodic-table/element/55/caesium
  7. Prohaska, T., et al. (2022, May 1). Standard atomic weights of the elements 2021 (IUPAC Technical Report). Pure and Applied Chemistry, 94(5), 573–600. https://doi.org/10.1515/pac-2019-0603
  8. Haynes, W. M. (Ed.). (2014, June 4). CRC Handbook of Chemistry and Physics. https://doi.org/10.1201/b17118
  9. Kaye, G W.C., & Laby, T H. Tables of physical and chemical constants. 15th Edition. United States.
  10. Sansonetti, J. E., & Martin, W. C. (2005, December). Handbook of Basic Atomic Spectroscopic Data. Journal of Physical and Chemical Reference Data, 34(4), 1559–2259. https://doi.org/10.1063/1.1800011
  11. Bondi, A. (1964, March). van der Waals Volumes and Radii. The Journal of Physical Chemistry, 68(3), 441–451. https://doi.org/10.1021/j100785a001
  12. Holden, et al. (2018, December 1). IUPAC Periodic Table of the Elements and Isotopes (IPTEI) for the Education Community (IUPAC Technical Report). Pure and Applied Chemistry, 90(12), 1833–2092. https://doi.org/10.1515/pac-2015-0703
  13. Zhang, et al. (2011, January 11). Corrected Values for Boiling Points and Enthalpies of Vaporization of Elements in Handbooks. Journal of Chemical & Engineering Data, 56(2), 328–337. https://doi.org/10.1021/je1011086
  14. Periodic Table of Elements: Los Alamos National Laboratory. (n.d.). Periodic Table of Elements: Los Alamos National Laboratory. https://periodic.lanl.gov/55.shtml
  15. C&EN: IT’S ELEMENTAL: THE PERIODIC TABLE – CESIUM. (n.d.). C&EN: IT’S ELEMENTAL: THE PERIODIC TABLE – CESIUM. https://pubsapp.acs.org/cen/80th/cesium.html?

Jay is an educator and has helped more than 100,000 students in their studies by providing simple and easy explanations on different science-related topics. With a desire to make learning accessible for everyone, he founded Knords Learning, an online chemistry learning platform that provides students with easily understandable explanations.

Read more about our Editorial process.

Leave a Comment