Cesium One of the most reactive elements of the Periodic Table

All about Cesium

Physical Properties

  • White, silvery, shiny metal
  • Opaque
  • Solid at room temperature
  • Very malleable
  • Ductile
  • Melting point of 28.5
  • Boiling point of 705
  • Conducts electricity
  • Density 1.90 grams per cm^2
  • Most Cesium compounds are soluble

Chemical Properties

  • Reacts violently with oxygen and water
  • In reaction with water, hydrogen gas is released which ignites immediately due to the heat given off from the reaction
  • Highly Toxic
  • Also reacts with acids, halogens, sulfur and phosphorous

The discovery of Cesium

The element cesium was discovered by German chemists Robert Bunsen and Gustav Kirchoff in 1860 through a spectroscopic analysis of Durkhiem Mineral Water. They observed blue lines in the spectrum of the mineral water and named it Cesium after the Latin word Caesius, meaning sky blue.

Spectrum of Durkheim mineral water

Uses of Cesium

Photo electric cell, atomic clock and optical glasses

Because Cesium is not a common element, it has few commercial uses. However, Cesium is used in

  • photoelectric cells, devices for changing sunlight into electrical energy
  • atomic clocks, clocks that are the most precise method for measuring time
  • cesium nitrate is used in optical glasses
  • as a catalyst in the hydrogenation of certain organic compounds.
  • as a getter, a material that combines with and removes trace gases from vacuum tubes because it combines with oxygen
  • and cesium 137, a radioactive isotope, is used in a variety of medical and industrial applications, for example, in medical radiation therapy devices for treating cancer
Bohr Rutherford diagram of cesium
Cesium on the periodic table

Cesium Explained

Cesium is found in group 1, period 6, on the periodic table making it one of the larger elements. It has 55 electrons and 1 valence electron. Because of its size and location, cesium has a small ionization energy, making it easy to take an electron from it. This is because it doesn’t require very much force to pull the only valence electron off of cesium. It is so far away from the nucleus that there isn’t very much positive charge from the protons in the nucleus holding on to it. Cesium also has a small electron affinity, making it harder to gain electrons, because there isn’t a strong pull from the protons in the nucleus. The protons are already holding 55 electrons and cesium would much rather give one electron up than gain 7 more. This is why it is so reactive.

Cesium and the environment

Cesium is a naturally occurring element found in rocks, soil and dust at low concentrates. Granite contains 1ppm (1 part per million) of cesium and sedimentary rocks contain about 4ppm. However, the cesium found in the environment is not the same as the highly reactive cesium on the periodic table, otherwise there would be explosion like reactions everywhere because cesium reacts violently with air and water. Cesium is only found in the environment as a stable isotope, cesium 133.

Pure Cesium

Additional Information about Cesium

  • Since cesium is easily ionized and has a high mass, cesium ions may one day be used as a propellant in ion engines on spacecraft.
  • Cesium has 12 isotopes, cesium 137 being the radioactive isotope and cesium 133 being the stable isotope found naturally

Works cited

  • Advameg, Inc. "Chemistry Explained." Cesium, Chemical Element. JRank, n.d. Web. 06 Oct. 2015. <http://www.chemistryexplained.com/elements/A-C/Cesium.html>.
  • "Chemical Properties of Cesium." Cesium - Cs. Lenntech, n.d. Web. 6 Oct. 2015. <http://www.lenntech.com/periodic/elements/cs.htm>.
  • Gagnon., Steve. "The Element Cesium." It's Elemental -. Jefferson Lab, n.d. Web. 06 Oct. 2015. <http://education.jlab.org/itselemental/ele055.html>.
  • Lew, Kristi. The Alkali Metals: Lithium, Sodium, Potassium, Rubidium, Cesium, Francium. N.p.: Rosen Central, 2009. Print. Understanding the Elements of the Periodic Table.
  • "Toxic Substances Portal - Cesium." Agency for Toxic Substances and Disease Registry. ATSDR, 21 Jan. 2015. Web. 06 Oct. 2015. <http://www.atsdr.cdc.gov/phs/phs.asp?id=575&tid=107>.

By Derrick Knill

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