Question

write a comparative study of the models of atom
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Answer 1

Answer:

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Compare all the proposed models of an atom.

J. Thomson: An atom as a whole is electrically neutral because the negative and positive charges are equal in magnitude. J. J. Thomson suggested that electrons are embedded in a sphere of a positive charge. Thomson’s model of the atom fails to explain Rutherford’s α-particle scattering experiment in which most of the fast-moving α-particles passed straight through the gold foil.

E. Rutherford: The gold foil experiments of Rutherford suggested that all the positive charge is located in a very small space which is 10 times the radius of an atom. Therefore,

Answer 2

J. Thomson: An atom as a whole is electrically neutral because the negative and positive charges are equal in magnitude. J. J. Thomson suggested that electrons are embedded in a sphere of a positive charge. Thomson’s model of the atom fails to explain Rutherford’s α-particle scattering experiment in which most of the fast-moving α-particles passed straight through the gold foil.

E. Rutherford: The gold foil experiments of Rutherford suggested that all the positive charge is located in a very small space which is 10 times the radius of an atom. Therefore, Rutherford gave a model in which electrons are revolving around the nucleus. He found that the size of the nucleus is very small as compared to the size of the atom. Rutherford’s model of the atom failed to explain the stability of the atom.

Neils Bohr: To explain the stability of an atom and atomic spectra, Bohr suggested that electrons are moving around the nucleus in orbits which have fixed energy shells. There is a loss or gain in energy of an electron when it moves from one orbit to the other. Only certain special orbits known as discrete orbits of electrons are allowed inside the atom. These orbits or shells are represented by the letters K, L, M, N,… or the numbers, n=1,2,3,4,…