(N/A) Alkali metals form predominantly ionic compounds. Alkaline earth metals also form ionic compounds,but they exhibit a greater tendency to form covalent compounds compared to alkali metals due to their higher charge density and smaller ionic radii.
$(b)$ Alkali metal oxides are strongly basic and dissolve in water to form strong hydroxides. Alkaline earth metal oxides are also basic,but less so than alkali metal oxides; their solubility in water increases down the group.
$(c)$ Both groups form oxosalts (like carbonates,sulfates,and nitrates) with oxoacids. Alkali metals form these more readily due to their higher reactivity.
$(d)$ The solubility of oxosalts of alkali metals is generally higher than that of alkaline earth metals,although this depends on the specific anion and the balance between lattice enthalpy and hydration enthalpy.
$(e)$ Alkali metal oxosalts are generally more thermally stable than those of alkaline earth metals. For example,$Na_2CO_3$ is stable to heat,whereas $MgCO_3$ decomposes upon heating to form $MgO$ and $CO_2$.