This lecture covers the fundamentals of Thomson scattering, including elastic scattering of photons, the Q-vector, atomic scattering factors, and the spatial distribution of elastic scattering by atoms. It also explores the database for atomic scattering factors and the scattering from a sulfur atom. The instructor discusses the spherical symmetry of electron clouds around atoms and the spatial dependence of scattering factors. The summary emphasizes the scattering amplitude from the entire electron cloud and the integration of scattering over atom volume, known as the atomic form factor.