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Video Example : Thomson’s model

Thomson’s model


  • electrons
  • protons
  • water melon model
  • neutral
  • cathode ray scope

Definition of Thomson’s model

Thomson’s model was the first atomic model. The plum pudding model, also known as the blueberry muffin model, of the atom by J. J. Thomson, who discovered the electron in 1897

More About Thomson’s model

  • In this model, the atom is composed of electrons, which Thomson still called "corpuscles”
  • G. J. Stoney had proposed that atoms of electricity be called electrons in 1894 surrounded by a soup of positive charge to balance the electrons' negative charges, like negatively charged "raisins" surrounded by positively charged "pudding"
  • The electrons (as we know them today) were thought to be positioned throughout the atom, but with many structures possible for positioning multiple electrons, particularly rotating rings of electrons
  • Atom was also sometimes said to have had a "cloud" of positive charge
  • Thomson atomic model, earliest theoretical description of the inner structure of atoms, proposed in 1900 by Lord Kelvin and strongly supported by Sir Joseph John Thomson who discovered electrons
  • Thomson held that atoms are uniform spheres of positively charged matter in which electrons are embedded
  • The plum-pudding model, it had to be abandoned on both theoretical and experimental grounds in favor of the Rutherford atomic model, in which the electrons describe orbits about a tiny positive nucleus
  • According to Thomson’s model, the electrons were like currants in a spherical Christmas pudding
  • That is the positive charge is spread all over the atom with negative electrons embedded in it
  • Thomson’s atomic model can be compared to a watermelon with red edible part being compared to positive charge and electrons embedded resembling the seeds in a watermelon
  • According to Thomson, an atom consists of a positive sphere in which negatively charged electrons are embedded in it
  • The negative and positive charges are equal in magnitude. So the atom is electrically neutral
  • Thomson's atomic model was called the plum pudding model
  • Thomson's atomic model was introduced right after Thomson's 1897 discovery of the electron, then called corpuscles
  • Thomson said that no matter where matter came from, it contained particles that were the same and are smaller than the atoms that matter is formed from
  • The model was a round thick liquidy substance whose total charge canceled out the charge of the electrons
  • He came to this conclusion by using a cathode ray scope


Drawbacks of Thomson model of an atom:-

    1) The electrons are moving around the nucleus
    2) Nucleus is not shown
    3) Neutron is not represented