Question

Why are potassium and caesium, rather than lithium used in photoelectric cells?

Solution

This is because potassium and caesium have much lower ionisation enthalpy than that of lithium. As a result, these two metals when subjected to light, emit electrons but lihtium does not. Hence potassium and caesium, rather than lithium is used in photoelectric cells.

Some More Questions From The s-Block Elements Chapter

Lithium has highest ionisation energy in group 1 elements, yet it is strongest reducing agent. Comment.

The softness of group 1 elements increases down the group with increasing atomic number. Give reason.

Which is the most reactive alkali metal and why?

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The S-Block Elements

Why are potassium and caesium, rather than lithium used in photoelectric cells?

Some More Questions From The s-Block Elements Chapter

Lithium has highest ionisation energy in group 1 elements, yet it is strongest reducing agent. Comment.

The softness of group 1 elements increases down the group with increasing atomic number. Give reason.

Which is the most reactive alkali metal and why?

Why alkali metals do not form M²⁺ions?

Name the radio active element in group 1. How does it resemble with the remaining elements of the group?

Why alkali metals are normally kept in kerosene oil?

Why lithium cannot be stored in kerosene?

Why does lithium form complexes?

Why are alkali metal ions diamagnetic and colourless?

Why are alkali metals the most electropositive in nature?

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NCERT Sample Papers

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For Daily Free Study Material Join wiredfaculty

The S-Block Elements

Why are potassium and caesium, rather than lithium used in photoelectric cells?

Some More Questions From The s-Block Elements Chapter

Lithium has highest ionisation energy in group 1 elements, yet it is strongest reducing agent. Comment.

The softness of group 1 elements increases down the group with increasing atomic number. Give reason.

Which is the most reactive alkali metal and why?

Why alkali metals do not form M2+ ions?

Name the radio active element in group 1. How does it resemble with the remaining elements of the group?

Why alkali metals are normally kept in kerosene oil?

Why lithium cannot be stored in kerosene?

Why does lithium form complexes?

Why are alkali metal ions diamagnetic and colourless?

Why are alkali metals the most electropositive in nature?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Why alkali metals do not form M²⁺ions?