This video lecture from Periodic Classification of Elements and Periodicity (F.Sc. second year Chemistry) covers: Energy released in dissolution in water and dependence on charge to size ratio of the atom or ion. Comparison of hydration energies of ions within a compound with the lattice energies involved and the solubility effects. The trends that are followed in groups and in periods. Find more e-learning material and educational video lectures in Urdu at maktab.pk. These videos are free to use for promotional and commercial purpose by keeping the credits to Maktab.