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The S-Block Elements

Question
CBSEENCH11007137
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Second ionisation enthalpies of alkali metals are much higher than those of the alkaline earth metals. Explain. 

Solution

Alkali metals have only one valence electron, while alkaline earth metals have two valence electrons. After the removal of one electron from alkali metals, they form M+which is a stable noble gas configuration. Removal of another electron from the unipositive ion of alkali metal, therefore, would require a very large amount of enthalpy.
On the other hand, after the removal of one electron from alkaline earth metals, they do not acquire stable noble gas configuration and still have a tendency to lose another electron. As a result, the second ionisation enthalpies of alkali metals are much higher than those of the alkaline earth metal. 

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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