Why do alkaline earth metals have higher melting points than group 1 elements ?

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?

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

The alkali metal having highest melting point is

Chemical elements having highest melting point

.Which of the alkali metal is having least melting point?

.Which of the alkali metal is having least melting point?

Why alkaline earth metal oxides are quite stable?

Why alkaline earth metal oxides are quite stable?

Why amines have higher boiling points than corresponding alkanes ?