According to Rutherford nuclear model of the atom,
A. most of the mass of the atom and all its positive charge are concentrated in a tiny nucleus at its center.
B. electrons revolve around the nucleus in their respective dynamically stable orbits.
C. the characteristic line spectra of atoms of different elements can be explained.
D. an atom is a spherical cloud of positive charges with electrons embedded in it.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A and B only
Rutherford’s model came from the alpha-particle scattering experiment: a few alpha particles bounced back, which showed that the positive charge and nearly all the mass sit in a tiny nucleus.
(A) most of the mass of the atom and all its positive charge are concentrated in a tiny nucleus at its center. — Correct. This is the central idea of the nuclear model.
(B) electrons revolve around the nucleus in their respective dynamically stable orbits. — Correct. The model pictures each electron in an orbit where the electrostatic attraction provides the centripetal force. Classical theory says such an electron should radiate and spiral in, which the model cannot explain, but the orbits are still part of what it proposes.
(C) the characteristic line spectra of atoms of different elements can be explained. — Incorrect. The model cannot explain the line spectra; Bohr’s model was needed for that.
(D) an atom is a spherical cloud of positive charges with electrons embedded in it. — Incorrect. This is Thomson’s plum pudding model, which the scattering experiment disproved.
NCERT (2026-27):
Electron Orbits – “The Rutherford nuclear model of the atom which involves classical concepts, pictures the atom as an electrically neutral sphere consisting of a very small, massive and positively charged nucleus at the centre surrounded by the revolving electrons in their respective dynamically stable orbits.”