This video lecture from Chemical Bonding (F.Sc. First Year Chemistry) covers the concept of ionic radii, reasons why cation radii is smaller than the atomic radii of the correspondent elements and Anion radii is larger than the atomic radii of correspondent elements. The general equation of interionic distance was also discussed. 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.