Atomic radius of alkali metals increases down the group and increases

1.	Atomic radius of alkali metals increases down the group and increases across period why?
Answer» On going down the atomic radius increases so ionisation energy decrease, this means that tendence of losing electron increases which implies increase in metallic character ( as electron affinity also decreases ). We know that oxides and hydroxides of metals are basic in nature. Thus basic character increases down the group.The basic nature can also be explained by electro negativity concept and acid ionisation constant (Ka). As the electro negativity of the orbital which contains the lone pair increases acidic strength increase.

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