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Post a LessonAnswered on 10 Apr Learn Unit 10-s -Block Elements (Alkali and Alkaline Earth Metals)
Sadika
Comparison of Alkali Metals and Alkaline Earth Metals:
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Answered on 13 Apr Learn Unit 10-s -Block Elements (Alkali and Alkaline Earth Metals)
Nazia Khanum
Potassium and cesium are sometimes preferred over lithium in photoelectric cells due to their lower ionization energy. Ionization energy is the energy required to remove an electron from an atom or ion in its gaseous state. Both potassium and cesium have lower ionization energies compared to lithium, making it easier to liberate electrons from their surfaces when exposed to light.
In photoelectric cells, the goal is to efficiently convert light energy into electrical energy by causing the emission of electrons from a material's surface (the photoelectric effect). Materials with lower ionization energies can release electrons more readily when illuminated by photons, leading to a more efficient conversion process.
However, the choice of material also depends on various factors such as cost, stability, and practical considerations in the specific application. While potassium and cesium may have advantages in certain cases, lithium could still be chosen for other applications where its properties are more suitable.
Answered on 13 Apr Learn Unit 10-s -Block Elements (Alkali and Alkaline Earth Metals)
Nazia Khanum
When alkali metals like lithium, sodium, or potassium dissolve in liquid ammonia, they form solutions that exhibit interesting color changes. This phenomenon is due to the formation of solvated electrons, which are free-moving electrons surrounded by a shell of solvent molecules (in this case, ammonia molecules).
Initially, as the alkali metal dissolves, the solution appears blue due to the presence of solvated electrons. These solvated electrons are responsible for the blue coloration. However, as more metal dissolves and the concentration of solvated electrons increases, the color of the solution changes to bronze, gold, or even reddish-brown.
This change in color occurs because as the concentration of solvated electrons increases, they begin to interact with each other, forming dimers and other aggregates. These aggregates absorb light differently, leading to a change in the observed color of the solution. The exact color observed depends on factors such as the concentration of solvated electrons and the specific alkali metal involved.
Overall, the color changes observed in alkali metal solutions in liquid ammonia are due to the formation of solvated electrons and their subsequent interactions, which alter the absorption properties of the solution.
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Answered on 29 Apr Learn Unit 10-s -Block Elements (Alkali and Alkaline Earth Metals)
Deepika Agrawal
"Balancing minds, one ledger at a time." "Counting on expertise to balance your knowledge."
Answered on 29 Apr Learn Unit 10-s -Block Elements (Alkali and Alkaline Earth Metals)
Deepika Agrawal
"Balancing minds, one ledger at a time." "Counting on expertise to balance your knowledge."
Answered on 29 Apr Learn Unit 10-s -Block Elements (Alkali and Alkaline Earth Metals)
Deepika Agrawal
"Balancing minds, one ledger at a time." "Counting on expertise to balance your knowledge."
Different concentrations of alkali metals in liquid ammonia results in different colours. The dilute solutions are blue in colour due to presence of ammoniated electrons. The concentrated solutions have copper bronze colour as ammoniated metal ions are bound by free electrons.
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Answered on 29 Apr Learn Unit 10-s -Block Elements (Alkali and Alkaline Earth Metals)
Deepika Agrawal
"Balancing minds, one ledger at a time." "Counting on expertise to balance your knowledge."
Answered on 29 Apr Learn Unit 10-s -Block Elements (Alkali and Alkaline Earth Metals)
Deepika Agrawal
"Balancing minds, one ledger at a time." "Counting on expertise to balance your knowledge."
Answered on 29 Apr Learn Unit 10-s -Block Elements (Alkali and Alkaline Earth Metals)
Deepika Agrawal
"Balancing minds, one ledger at a time." "Counting on expertise to balance your knowledge."
Take Class 12 Tuition from the Best Tutors
Answered on 29 Apr Learn Unit 10-s -Block Elements (Alkali and Alkaline Earth Metals)
Deepika Agrawal
"Balancing minds, one ledger at a time." "Counting on expertise to balance your knowledge."
All these elements play an important role in the biological functioning of the human body. Calcium also helps in maintaining the haemostasis, and magnesium helps in building and strengthening bones. Some of these minerals are present in high abundance in the human body and some are present in less amount.
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