Question

what is the most reactive alkali metal and why?
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Answer 1

Caesium

Caesium, the fifth alkali metal, is the most reactive of all the metals. All the alkali metals react with water, with the heavier alkali metals reacting more vigorously than the lighter ones.

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Answer 2

Answer:

caesium

Alkali metals have a tendency to lose the single valence electron and form +ve ion and gain inert gas configuration but in case of cesium, the distance of the valence electron is maximum. So, force of attraction by the nucleus is least, hence, it is more reactive.