Atom the truth part 2

The MYSTERY of ATOM

           In the previous topic we studied about the basic structure of atom which consist of nucleus and shells or orbits where electrons revolve. The structure of atom and the information about it we know today is the result of research work and studies of many scientists who worked day and night to discover the facts about it. Now we shall study about the atomic models which was proposed by J.J Thomson, Lord Rutherford, Neil Bohr and many more.

                J.J Thomson atomic model:

          Initially J.J Thomson took a step forward to explain the structure of atom through his atomic model in 1905, when only electron and proton was discovered. In his model he suggested that an atom is basically the sphere of positive charge proton in which the negatively charged electrons are embedded like the chocolate chips present in a cake.          

          This model was a initial step towards the structure of atom however it was rejected as it couldn’t explain the any observed phenomena about atom.

             Lord Rutherford atomic model:                                                        

Lord Rutherford in 1911 proposed his atomic model which was the conclusion of his famous experiment on gold sheet on which alpha rays were bombarded. In his experiment, he concluded and predicted his atomic model which has resemblance with the solar system.

 He used the principles of classical mechanics on the atom. The important points in his models are as follows.

    1)- There is a rigid structure in the center of atom which he called the nucleus.

    2)- There is same number of electron and proton in any atom therefore it is electrically neutral in     nature.

    3)- The mass of an atom is concentrated in this central part, the nucleus.

    4)- This central part must have positive charge.

    5)- The electrons of the particular atom in circular orbits around the nucleus like the planets     around the sun.

6)- As for as electron revolves around the nucleus it should evolve energy, which is one of the fundamentals of classical mechanics that every thing in motion evolves energy. As an electron is in state of continuous motion therefore it should continuously evolve energy and due to this an electron should displace from its initial position each time and take the new position nearer to the nucleus, simultaneously it should sink into the nucleus. As shown in the figure below

               Thus Rutherford model was giving an idea of collapsing atom but as we observe atoms don’t destroy itself and neither it happens that an electron radiates or evolve energy moving in the same orbit because when we take the spectrum of any atom it shows only discrete spectral lines not the continuous spectrum. It was the failure of his model that he used principles of classical mechanic to explain his model However his model was a great step to understand the structure of atom.

               It was Rutherford, who for the first time observed that mass of an atom is more then the mass of proton (almost double) in the atom so, he predicted the existence of another subatomic particle having similar mass like proton but no charge (neutral). This was discovered in 1930 by James Chadwick where it was named as neutron.

             The further models will be written and discussed in other topics, if you like the above content and if it was helpful to you then please support us and help us to share the information to reach to everyone.