This lecture covers the Quantum Mechanical Model, starting with Louis de Broglie's wave-particle duality concept and Erwin Schrödinger's wavefunction equation. It explains the uncertainty principle of Heisenberg, the solutions of the Schrödinger equation, and the quantum numbers defining the orbitals of an atom. The lecture also delves into electron probability, radial distribution functions, and the interpretation of the electron as a wave surrounding the nucleus.