The arrangement of fundamental particles in the atom is called atomic structure.
Various atomic models were proposed by different scientists.
Rutherford proposed atomic model based on the α - ray scattering experiment.
QUANTUM THEORY OF RADIATION In 1901 Max Plank proposed Quantum theory of Radiation from hot (black) body studies. A hot body radiates (emits) energy not in continuous waves but in small units of waves. When atoms or molecules absorb or emit radiant energy in quanta (a small packet of energy) or photons.