This video lecture from Transition Elements (F.Sc. second year Chemistry) covers: Concept of Orbits, Orbitals & Suborbitals , The various quantum numbers, The Madelung Rule, Aufbau Principle, The Pauli’s Exclusion Principle, and the Hund’s Rule which are followed in the filling of various orbitals of atoms. Partial filling of d orbitals is explained. Inner/Outer & Typical/Non-typical based classification is 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.