This video lecture from Periodic Classification of Elements and Periodicity (F.Sc. second year Chemistry) covers: Definition of pure conductors and the factors upon which resistance and conductance depends. The relationship between bond type i.e ionic,covalent and metallic and examples from groups and 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.