Reducing power of alkaline earth metals

[aim1732]

Why is standard reduction potential of beryllium and magnesium lower as compared to heavier members of the group while the reverse is true for alkali group? I read somewhere that this is due to more negative hydration enthalpies of these metals but shouldn't it make oxidation of these metals more favoured?

 

[Char. Limit]

Well, going by this table...

http://www.rsc.org/chemsoc/visualelements/Pages/data/intro_groupi_data.html

Lithium seems to be an anomaly, while Potassium, Rubidium, and Cesium have a lower SRP than sodium.

 

[aim1732]

Yes but my question was something else. I read in a book that reducing power of Li is due to its high hydration enthalpy. But somewhere else the authors also attributed the low reduction power of beryllium and magnesium to the same cause - high hydration enthalpy. Any ideas?