Question

how the metallic character of k is greater than cs

Answer 1

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The tendency of an atom to lose an electron and form a positive cation, making that atom act like a metal is called metallic character.

Metallic characteristics decrease from left to right across a period. This is caused by the decrease in radius of the atom that allows the outer electrons to ionize more readily.

Metallic character depends upon ionization energy. 

Therefore Cs has more electropositive nature (tendency to form cation easily) than K, i.e. 
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