Explain why alkaline earth metals are harder than alkali metals ?

Assertion (A): Alkaline earth metals are harder than alkali meatals. Reason (R ): Atomic radii of alkaline earth metas are smaller thant the corresponding alkali metals in the same period.

The alkaline earth metal harder than glass

Alkaline earth metal salts are:

Alkaline earth metals show:-

The first ionisation enthalpies of the alkline earth metals are higher than that of alkali metals but second ionisation ethalpies are smaller, why?

Lightest alkaline earth metal is