early atomic models

. The Indian philosopher Kanad (600 B.C) was of the view that matter consists of eternal and imperceptible particles called parmanus. The combination of these parmanus in different proportions forms matter. Democritus (400 B.C) a Greek philosopher proposed that matter was made up of very tiny parti..

Quantum Mechanical Model of the Atom - Two new theories came to substantially modify Bohr's Atomic model. They a..

Bohr's Model of an Atom - Rutherford's model had a major drawback. It could not explain why ultimately electrons did not fall into the nucleus by taking a spiral path. This was in concurrence with the electromagnetic theory that states 'if a charged particle undergoes ..

Rutherford proposed that electrons revolve at high speed in circular orbits around the positively charged nucleus. But according to the electromagnetic theory, if a charged particle were accelerated around another charged particle then there would be a continuous radiation of energy. The loss of ..

Rutherford's model had a major drawback. It could not explain why ultimately electrons did not fall into the nucleus by taking a spiral path. This was in concurrence with the electromagnetic theory that states 'if a charged particle undergoes accelerated motion then it must radiate ..

In 1913, Neils Bohr proposed a model of an atom based on the Planck's quantum theory of radiation. The basic postulates of Bohr's theory are: An atom consists of a small, heavily positively charged nucleus around which electrons revolve in definite circular paths ca..

Wave nature of material objects In 1924, de Broglie's suggested that all material objects including an electron have a dual character; they behave as particles as well as waves. The wavelength associated with a particle of mass 'm', moving with velocity 'v' is given by de Broglie's relation as: ..

J. J Thomson the discoverer of the electron believed that the atom is a uniform sphere of positive charge with electrons (raisins) embedded in it. This model explained the electrical neutrality of atom, but it failed to explain how these fundamental particles were a..

(i) Every atom consists of a nucleus containing the entire +ve charge. The whole mass of atom is concentrated at this core. (ii) The size of the nucleus i.e., 10 - 1 5 m is very small compared to the size of the atom (i.e., 10 - 1 0 m). (iii) The atom..