Which one of the following scientists mentioned that an electron in an atom could revolve in certain stable orbits without the emission of radiant energy ?

Niels Bohr proposed his atomic model in 1913 to address the stability issues of the Rutherford model. According to classical electromagnetic theory, an accelerating charged particle (like an orbiting electron) should continuously radiate energy and eventually spiral into the nucleus.

Bohr introduced the following postulates to resolve this:

• Electrons revolve around the nucleus only in certain discrete, stable orbits known as stationary states or energy levels.
• While an electron is in one of these permitted orbits, it does not radiate energy, ensuring the atom's stability.
• Energy is emitted or absorbed only when an electron jumps from one orbit to another.

In contrast, Ernest Rutherford proposed the planetary model but could not explain orbital stability. J.J. Thomson suggested the 'Plum Pudding' model, and Albert Einstein is best known for the photoelectric effect and relativity.