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Cesium, also known as Caesium, is an inorganic compound whose atomic number is 55 in the periodic table. It is most commonly found in the form of Cesium chloride (CsCl) and cesium nitrate (CsNO3).
- Cesium is a soft and silvery alkali metal that has only one stable isotope, cesium-133.
- The metal was discovered by Gustav Kirchhoff and Robert Bunsen in the year 1860.
- It is one of the five metals that is liquid at room temperature.
- The process of electrolysis of a molten cesium cyanide mixture can isolate the compound.
- It belongs to the group 1 of the periodic table.
- For commercial use, caesium is obtained from lithium production.
- The compound is mostly obtained by mining pollucite.
Key Terms: Cesium, Cesium Hydroxide, Hydrogenation, Ionization, Fractional Distillation, Organic Compound, Isotopes, Alkali Metals, Electronic Configuration, Sodium, Fractional Distillation, Ore, Alloy
What is Cesium?
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Cesium is an inorganic chemical element typically found in minerals like pollucite and lepidolite. It was discovered by Gustav Kirchhoff and Robert Bunsen in the year 1860.
- He performed a spectroscopic analysis of Durkheim's mineral water.
- The name cesium comes from Latin origin.
- In Latin, the word 'caesius' means sky blue.
- When burnt, the element emits a blue flame colour, hence giving it the name caesium.
- Cesium has no biological importance and is likely not harmful to living beings.
- Since it can be easily ionized, it has the potential to be used as fuel in the propulsion of space crafts in future.
The electron shell configuration of cesium is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 6s1.
- The radioactive cesium has a half-life of approximately 30 years.
- Caesium is highly reactive with water and easily gets ignited on coming in contact with it.
- It is used in industrial gauges, hydrology and medical applications.
Cesium
Preparation Of Cesium
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Caesium is extracted primarily from pollucite using three methods, namely alkaline decomposition, acid digestion, and direct reduction. Obtaining pure Cesium naturally is nearly impossible as it is highly reactive.
- Cesiu is frequently contaminated with rubidium.
- To obtain pure caesium, ores of cesium and rubidium are crushed and heated with sodium at 650° Celsius, which forms an alloy.
- The alloy is then separated by fractional distillation.
- Caesium is usually sold in the form of cesium azide (CsN3) because pure cesium is highly reactive.
- It is then obtained by heating cesium azide when required.
Structure of Cesium
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| Chapter Related Concepts | ||
|---|---|---|
| Unit & Measurement | Nitrogen | Rubidium |
| Cis-Trans Isomers | Versatile Nature of Carbon | Acids Bases and Salt |
Properties of Cesium
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Some important properties of Cesium are as follows:
- Cesium is silvery to gold in color.
- The metal is very delicate to touch
- This compound is very rare, being only 3ppm available on the earth’s crust.
- It is very reactive in nature and can react with air
- Caesium reacts violently with water and can cause an explosion if not carefully handled.
The tabulated information about properties of Cesium are as follows:
| Category | Data |
|---|---|
| Group | 1 |
| Period | 6 |
| Block | s |
| Atomic number | 55 |
| State at 20°C | Solid |
| Electron configuration | [Xe] 6s1 |
| ChemSpider ID | 4510778 |
The properties of cesium is divided into physical and chemical properties are as follows:
Physical Properties of Cesium
The physical properties of Cesium are as follows:
- Cesium is found in mineral ores like pollucite and lepidolite.
- The total number of electrons in the metal is 55.
- It has an ionisation energy of approximately 375.7 kJ/mol.
- The atomic symbol of the caesium is Cs, and its atomic weight is 132.905.
- Cesium is solid in nature at room temperature.
- The melting point of a compound is 28.5 degrees Celsius.
- Cesium boils at a temperature of 671 degrees Celsius.
The tabulated information about physical properties of Cesium are as follows:
| Category | Data |
|---|---|
| Symbol | Cs |
| Atomic number | 55 |
| Density | 1.93 g/cm3 |
| Melting point | 28.5°C |
| Boiling point | 671°C |
| State of matter | Solid at room temperature |
| Colour | Silvery-gold |
| Hardness | 0.2 Mohs |
| Atomic mass | 132.90545 u |
| Abundance in Earth’s crust | 2 parts per million (ppm) |
Chemical Reactions of Cesium
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Cesium is highly reactive in nature and can even react with air molecules. Here is some example of chemical reactions shown by cesium
- Cesium reacts violently with water and forms cesium hydroxide (CsOH) which is given as:
2Cs(s)+2H2O(l)→2CsOH(aq)+H2(g)
- It is the strongest known base and even reacts with glass.
- The compound is most commonly found in the form of Cesium chloride (CsCl) and cesium nitrate (CsNO3).
- It has an oxidation state of +1, which means it can easily lose electrons with cation.
- The metal reacts with an acid to form caesium salt and hydrogen.
- Since it is highly corrosive in nature, as a result, it cannot be stored in metal containers.
- Exposure to radioactive caesium can cause damage to cells.
Uses of Cesium
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Cesium has the second lowest melting point with mercury being the first so it has a very limited uses which are as follows:
- Cesium is used as a getter, which combines with gases and reduces its traces in a vacuum environment.
- It is also used as a catalyst in the hydrogenation of organic compounds
- The compound is also used in atomic clocks, also known as cesium clocks.
- It is used in the synthesis of certain drugs and chemicals.
- The metal is used in the manufacturing of photoelectric cells, which convert light energy into electrical energy.
- Caesium is used for the drilling of fluids from oil wells.
Read More:
| Class 11 Chemistry Related Concepts | ||
|---|---|---|
| Atoms & Molecules | Difference Between Element And Compounds | Atomic And Molecular Masses |
| Emulsions | Isotopes and Isobars | Transuranium Element |
Things to Remember
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- Cesium atoms have 55 electrons in their orbit, and their electronic shell structure is [2, 8, 18, 18,8, 1].
- It is an extremely soft, silvery-gold coloured metal which melts easily on being slightly warmer.
- The compound tends to form more positive ions easily, making it more electropositive than potassium.
- Cesium is used in ion engines for spacecraft because of its easy ionization.
- It is used for expeling oxygen from lights and vacuum tubes.
Previous Year Questions
- The Interionic Distance For Cesium Chloride
- Which Of The Following Is Not A Periodic Property….
- Porbitals In A Given Shell Can Accommodate Upto…
- The Value Of IE_1IE_2IE_3IE_4 And IE_5 Of An E…..
- Which Of The Following Has The Smallest Size….
- Which Of The Following Oxides Would Be Reduced By…. [UPSEEE 2019]
- Which Of The Following Electronic Configuration Is….. [WEBJEE 2018]
- Among The Following Choose The Correct… [JIPMER 2019]
- Which Is The Correct Increasing Order Of Ionization…
- The Element With The Atomic Number 118 Will Be… [NEET 1996]
- In Which Of The Following The Election Gain…. [AP EAPCET 2019]
- Which Of The Following Is Not True An Element With………...
- Which Of The Following Has The Highest First….. [AP EAPCET 1998]
- Which Among The Following Factors Is The Most…. [JCECE 2018]
- Which Of The Following Has Minimum Ionization….
- The Correct Order Of Decreasing Electronegativity… [KEAM]
- The Increasing Order Of Electronegativity Of The…. [KEAM]
- Which Will Reduce Zinc Oxide To Zinc… [BCECE 2006]
- The Correct Order Of Electronegativities Of N O F… [KCET 2012]
- The Radii Of TextFtextFtextO And TextO2 Are In…. [AP EAPCET 1998]
Sample Questions
Ques: What makes Cesium so expensive? (2 Marks)
Ans: Cesium is one of the rarest elements and does not have many commercial uses. It has to go through a difficult and lengthy process to break the chemical bond. It can result in the production of the metal in its pure state.
Ques: What is the atomic no. of Cesiums and also mention its shell structure? (2 Marks)
Ans: Atomic no. of Cesium is 55 and their electronic shell structure is [2, 8, 18, 18,8, 1].
Ques: Why is the extraction of pure Cesium difficult? (1 Mark)
Ans: Cesium is usually found combined with Rubidium and other alkali metals. The similarity in the property of the alkali metals makes it difficult to separate Cesium from other alkali metals.
Ques: What type of bonds does Cesium have? (2 Marks)
Ans: Cesium falls under the category of group 1 elements which are recognized as alkali metals. Cesium, being the most electropositive element on the periodic table, easily gives up its electron to form an ionic bond. It also shows violent reactivity in the presence of air and water.
Ques: How can cesium affect health? (4 Marks)
Ans: The health hazards of Cesium are:
- When consumed, it is moderately toxic
- It will cause thermal burns when it ignites
- It causes eye and skin burns if exposed for a longer time
- Exposure for a longer period can also cause hyper irritation, skin ulcer, and nervousness
Ques: What are the uses of cesium? (3 Marks)
Ans: Cesium has the second lowest melting point of metals first being mercury so it has a very limited use case
- Cesium's hue ranges from silver to gold.
- It's quite delicate to touch the metal.
- The earth's crust contains only 3 parts per million of this extremely rare chemical.
- It can react with air and is highly reactive in nature.
- When handled carelessly, caesium interacts violently with water and can explode.
Ques: Which process is used to extract cesium? (3 Marks)
Ans: Obtaining pure Cesium naturally is nearly impossible as it is highly reactive and is frequently contaminated with rubidium (which is similar to Cesium).
- To obtain pure Cesium, ores of cesium and rubidium are crushed and heated with Sodium at 650° Celsius which Forms an alloy.
- This alloy is then separated by fractional distillation
- Cesium is usually sold in the form of cesium azide (CsN3) because pure cesium is highly reactive
- Cesium is then obtained by heating cesium azide when required.
Ques: Is cesium an active metal? (2 Marks)
Ans: Cesium is one of the most active alkali metals. It is a soft and silvery-gold metallic element of group 1. The other active elements that belong to groups IA and IIA are lithium, sodium, potassium, Rubidium, calcium, strontium, and barium.
Ques: Mention properties of cesium? (5 Marks)
Ans: All Chemical compounds have physical and chemical properties. Here are some properties of Cesium
- It is silvery to gold in color
- It is very delicate to touch
- It is very rare (only 3ppm available on earth’s crust)
- It is very reactive in nature and can react with air
- It reacts violently with water and can cause an explosion if not carefully handled
- It is found in mineral ores like pollucite and lepidolite.
Ques: State a few examples of chemical reactions of cesium? (3 Marks)
Ans: Cesium is highly reactive in nature and can even react with air molecules. Here is some example of chemical reactions shown by Cesium
- Cesium reacts violently with water and forms cesium hydroxide (CsOH)
- It is the strongest known base and even reacts with glass.
- Cesium is most commonly found in the form of Cesium chloride (CsCl) and cesium nitrate (CsNO3).
When a person takes an overdose of propranolol, the chances of cardiac arrest, cardiogenic shock, and seizures increase. The person should immediately visit to doctor.
Ques. What is Ionisation energy of cesium? (3 Marks)
Ans. Ionisation energy is the energy necessary to remove one electron from a neutral atom. At 375.7 kJ/mol, the initial ionization energy for cesium is rather low.
- The atom's enormous size contributes to its low ionization energy because the valence electron is comparatively far from the positively charged nucleus.
- This result in a lesser attraction between the two.
- The ionization energies of the second and third phases are 2300 kJ/mol and 3820 kJ/mol, in that order.
- The reason for this constant rise in ionization energy is that electrons are attracted to nuclei more strongly the closer they are to the latter.
Ques. List five uses of propranolol? (4 Marks)
Ans. Some uses of propranolol are:
- Propranolol treats migraine and cluster headaches.
- It is also used to treat hyperhidrosis.
- Propranolol can also be used for essential tremors.
- Cases of thyrotoxicosis are also treated by propranolol.
Ques. How cesium is discovered? (3 Marks)
Ans. Using a newly developed tool called a spectroscope, two German chemists named Robert Bunsen and Gustav Kirchhoff made the initial discovery of cesium in 1860 while examining the spectral lines of spring water from Durkheim, Germany.
- They just so happened to spot an unidentifiable brilliant blue line in the spectrum.
- After much investigation, the blue line in the mineral water turned out to be a new element called Cesium.
- It is derived from the Latin word "caesius," which means "sky blue."
Ques. Anwer the following: (A) Who founded cesium
(B) How is pure cesium obtained? (2 Marks)
Ans. (A) Gustav Kirchhoff and Robert Bunsen discovered cesium in the year 1860 by performing a spectroscopic analysis of Durkheim's mineral water.
(B) To Obtain pure cesium, ores of cesium and rubidium are crushed and heated with Sodium at 650° Celsius which forms an alloy.
Ques. What is electronegativity of Cesium? (2 Marks)
Ans. Cesium has a comparatively low electronegativity, measuring roughly 0.79 on the Pauling scale. This is due to its low effective nuclear charge owing to its large atomic radius, which makes it easier for the outermost electron to be ejected from the atom. Cesium is hence a very reactive metal that easily loses its outermost electron to generate a positive
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