Question

Which of the following is not a postulate of Rutherford’s atomic model?

• A. All atoms contain a small, heavy and positively charged body at its centre called nucleus.
• B. Entire mass of an atom resides in its nucleus.
• C. Negatively charged electrons revolve around the nucleus at a very high speed.
• D. The electrons always move in certain stationary orbits which have fixed energy

Answer 1

The correct option is D The electrons always move in certain stationary orbits which have fixed energy

The postulates of Rutherford’s model of an atom are as follows:

• An atom consists of a positively charged, dense and very small nucleus containing all the protons and neutrons.
• Almost the entire mass of an atom is concentrated in the nucleus.
• The nucleus is surrounded by negatively charged electrons.
• The electrons revolve around the nucleus in circular paths at very high speeds.
• The electrostatic attraction between the positively charged nucleus and negatively charged electrons holds the atom together.
• An atom is electrically neutral.

It was Bohr who proposed that the electrons move in certain stationary orbits and each orbit is associated with a definite amount of energy.
Hence, the correct answer is option (d).