The atomic radii of alkaline earth metals are smaller than those of the corresponding alkali metals. Explain, why?

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.

Alkaline earth metals have lower melting point than correspondig alkali metals.

The densities of alkaline earth metals are much smaller than those of alkali metals.

Alkaline earth metals show:-

(a) Why alkaline earth metals are harder, have higer melting ponts and higher densities than the alkali metals? (b). Why the atoms of alkaline earth metals are smaller than the corresponding alkali metals? (c ). Why alkaline earth metals have high electrical and thermal conductivities? (d). What is black ash? (e). Why the variation in physical properties of alkaline earth elements is not as regular as in the case of alkali metals?

The least abundant alkaline earth metal is

How many alkaline earth metals are known?

The ionisation enthalpy of alkaline earth metals is

(a). Which alkaline earth metals do not give characteristic colour to the Bunsen flame? (b). Why alkaline earth metals do not form tripositive ions? (c ). Why alkaline earth metals are diamagnetic, but alkali metals are paramagnetic? (d). Why the first inonisation enthaply pf alkaline earth matals is higher than those of corresponding alkali metals? (e). Why alkaline earth metals are less electropositive than corresponding alkali metals?

The crystaline salts of alkaline earth metals contain more water of crystallisation than the corresponding alkali metal salts. Why?