Caesium is one of the most electropositive and most alkaline of all the elements. It is silvery gold, ductile and soft and one of only three metals that are liquid at or around room temperature.
Its symbol is Cs and the ground state electron configuration is [Xe]6s1. It is a member of the group 1 alkali metals and so it is obviously an s-block element.
As you can see from the picture below the shell structure of Caesium is 2.8.18.18.8.1 and so its atomic number is 55.
Caesium is produced by the reaction of metallic Sodium with hot molten Caesium Chloride:
Na + CsCl ↔ Cs + NaCl
The method used to extract the Caesium, results in it being relatively free from sodium impurities. Distillation can be used to obtain pure Caesium.
The surface of a freshly cut segment of Caesium is bright and shiny. However, the longer this surface is exposed to the air, the more it dulls due to its reactions with the Oxygen and moisture in the air. When Caesium is burned in air the result is an orange compound called Caesium Superoxide:
Cs(s) + O2(g) → CsO2(s)
Caesium reacts with ice at temperatures above -116° and has an explosive reaction with water. This reaction is extremely exothermic. It results in a colourless, basic solution due to the formation of Caesium Hydroxide and Hydrogen gas. This reaction occurs so fast that if it was to take place in a glass vessel, the glass would end up shattered! This reaction is faster than that of
Rubidium with water.
2Cs(s) + 2H2O → 2CsOH(aq) + H2(g)
Caesium reacts very strongly with all the halogens:
2Cs(s) + F2(g) → CsF(s)
2Cs(s) + Cl2(g) → CsCl(s) + H2(g)
2Cs(s) + Br2(g) → CsBr(s)
2Cs(s) + I2(g) → CsI(s)
These are all called Caesium Halides.
Caesium doesn't have very many uses. The most common are:-
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