What is Cesium? Origin / Meaning of the name Cesium
The word Caesium originates from the Latin word 'caesius' which means "sky blue" from the bright blue lines in its spectrum.

What is Cesium? Periodic Table Group and Classification of the Cesium Element
Elements can be classified based on their physical states (States of Matter) e.g. gas, solid or liquid. This element is a solid. Cesium is classified as an "Alkali Metal" and located in Group 1 elements of the Periodic Table. An Element classified as an Alkali Metal is a very reactive metal that does not occur freely in nature. Alkali metals are soft, malleable, ductile, and are good conductors of heat and electricity. Nearly 75% of all the elements in the Periodic Table are classified as metals which are detailed in the List of Metals.

What is Cesium? Occurrence of the Cesium Element
Cesium is found in the mineral pollux, or pollucite, which occurs on the island of Elba, in South Africa, in the United States in Maine and South Dakota, and in Manitoba, Canada.

Abundances of the element in different environments
% in Universe 8×10^-8%
% in Sun 8×10^-7%
% in Meteorites 0.000014%
% in Earth's Crust 0.00019%
% in Oceans 5×10^-8%
% in Humans 2×10^-6%

Medical Uses of Cesium - Health and Treatments
Interesting information on the Medical Uses of Cesium, Health and Treatments. Radium salts have been used as radiation sources in the treatment of cancer but are gradually being replaced in such therapy by cobalt and cesium.

Associated Uses of Cesium
Atomic clocks
Removes air traces in vacuum tubes
Ion propulsion systems
Medical
Photoelectric cells
Cesium vapor
Magnetometer

What is Cesium? The Properties of the Cesium Element
Name of Element : Cesium
Symbol of Element : Cs
Atomic Number of Cesium : 55
Atomic Mass: 132.90546 amu
Melting Point: 28.5 °C - 301.65 °K
Boiling Point: 678.4 °C - 951.55005 °K
Number of Protons/Electrons in Cesium : 55
Number of Neutrons in Cesium : 78
Crystal Structure: Cubic
Density @ 293 K: 1.873 g/cm3
Color of Cesium : silvery-white

Facts about the History of the Discovery of Cesium Element
Cesium was discovered by Fustov Kirchoff and Robert Bunsen in 1860 from mineral water found in Dürkheim, Germany. It was the first element discovered by spectrum analysis.

Robert Wilhelm Bunsen
Robert Wilhelm Bunsen (1811-1899) invented many lecture-room and laboratory appliances, most famously the Bunsen burner. He also invented the spectroscope and with it discovered rubidium and caesium; greatly perfected methods of electrolysis, inventing a new battery; made many investigations among metallic and organic substances.

Robert Bunsen (1811 - 1899)

Cesium as on the Periodic Table
Check out Cesium on the Periodic Table which arranges each chemical element according to its atomic number, as based on the Periodic Law, so that chemical elements with similar properties are in the same column. Our Periodic Table is simple to use - just click on the symbol for Cesium as on the Periodic Table for additional information and for an instant comparison of the Atomic Weight, Melting Point, Boiling Point and Mass - G/cc with any other element. An invaluable source of facts and information as a Chemistry reference guide.

Other elements classified as Alkali Metals
Alkali metals are soft, malleable, ductile, and are good conductors of heat and electricity. The other elements contained in this classification are as follows:

• Lithium
• Sodium
• Potassium
• Rubidium
• Francium

What is Cesium - IUPAC and the Modern Standardised Periodic Table
The Standardised Periodic Table in use today was agreed by the International Union of Pure Applied Chemistry, IUPAC, in 1985 and now recognises more periods and elements than Dimitri  Mendeleev knew in his day in his day but still all fitting into his concept of  the "Periodic Table" in which Cesium is just one element that can be found.

Learn about what is Cesium with these fast facts...
These articles contain facts and information relating to Cesium and each of the other elements including the Periodic Symbol,  group, classification, properties and atomic number which is often referred to as the Periodic Table Number. Test your knowledge of chemistry and the Periodic Table by completing the Element Symbols and Atomic Numbers on our Blank Periodic Table. Chemistry students will also find a helpful section on Chemical Formulas.