Q88 / 90 · JEE Main 2024 (29 Jan Shift 2) · Physics

Given below are two statements:
Statement I: Most of the mass of the atom and all its positive charge are concentrated in a tiny nucleus and the electrons revolve around it, is Rutherford's model.
Statement II: An atom is a spherical cloud of positive charges with electrons embedded in it, is a special case of Rutherford's model.
In the light of the above statements, choose the most appropriate from the options given below.

  • A
    Both statement I and statement II are false
  • B
    Statement I is false but statement II is true
  • Correct answer
    C
    Statement I is true but statement II is false
  • D
    Both statement I and statement II are true

Solution

Rutherford proposed that most of the mass of an atom is concentrated in a small, dense nucleus at the centre, which contains positively charged protons. Electrons, carrying negative charge, revolve around the nucleus in orbits.

In the Bohr model, electrons do not move in random orbits but have specific energy levels or shells around the nucleus. The electrons are not in a "spherical cloud" but are found in discrete orbits at fixed distances from the nucleus. Rutherford's model, on the other hand, did not specify the fixed orbits of electrons and was later refined by Bohr to explain the stability of atoms.

Hence, statement I is true but statement II is false.

Hence, the correct answer is option: 'C'.

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