Humber Admissions Practice Test

Which model visualizes electrons as planets revolving around the sun?

1. Quantum Model

2. Rutherford Model

3. Bohr Model

4. Dalton's Model

The correct answer is: Bohr Model

The correct choice is the Bohr Model because it conceptualizes electrons as being in specific orbits around the nucleus, much like planets orbiting the sun. This model, proposed by Niels Bohr in 1913, was a fundamental development in understanding atomic structure. In this analogy, the nucleus of the atom acts as the sun at the center, while the electrons travel in distinct paths or energy levels, corresponding to the orbits of planets. This model was pivotal as it introduced quantized energy levels, meaning electrons can only exist in certain allowed states and cannot be found in between these levels. The visual representation helped to simplify the complex idea of electron behavior and has played a crucial role in the historical progression toward the more advanced quantum mechanical models. Other models, such as the Quantum Model, emphasize the probabilistic nature of electron locations rather than fixed orbits, while the Rutherford Model primarily focused on the structure of the atom with a dense nucleus but did not incorporate quantized electron paths. Dalton's Model is an earlier atomic theory that treated atoms as indivisible particles without reference to electron behavior or structure. Thus, the Bohr Model remains distinct for its planetary-like visualization of electron motion.