1. Compare the location of electrons in an atom based on Bohr's theory with the location of electrons in an atom based on the current atomic theory.
2. Rutherford performed his gold-foil experiment to test Thomson's plum-pudding model. Describe what the results would have looked like if it had supported the plum-pudding model instead of contradicting it.
Please explain concisely.
Answer (3)
Bohr said that electrons orbited the nucleus in fixed circular orbits. In reality, electrons are not in fixed orbits, but can be predicted by the quantum mechanical model and orbitals which indicate places with high probability of finding an electron.
Rutherford found that some of his particles bounced off the gold foil because of the strongly positive nucleus. If the results had supported Thompson's model, all particles would have passed through with very minimal deflection.
Bohr's theory describes electrons in fixed orbitals, whereas the current atomic theory uses electron clouds with probabilities for electron locations. Rutherford's gold-foil experiment contradicted the plum-pudding model, as it showed significant deflection of alpha particles, indicating a nucleus in the atom.
Comparison of Bohr's Theory and Current Atomic Theory on Electron Location
According to Bohr's theory, electrons are located in fixed orbitals around the nucleus, with each orbit holding a certain number of electrons. These orbits were seen as distinct paths much like the planets orbiting around the sun. In contrast, the current atomic theory discards these fixed orbits in favor of electron clouds or orbitals where the probability of finding an electron is the highest. This theory relies on quantum mechanics and the uncertainty principle, indicating that we can only predict the likelihood of an electron's location rather than specifying a clear path.
Rutherford’s Gold-Foil Experiment
If Rutherford's gold-foil experiment had supported the plum-pudding model, the alpha particles would have passed through the gold foil with very little deflection, as it was hypothesized that a uniform spread of positive charge and electrons (like plums in pudding), would not offer significant resistance to the massive alpha particles. However, Rutherford observed that many alpha particles were deflected at various angles, with some reflecting straight back, which contradicted Thomson's model and indicated the presence of a dense, positively charged nucleus, leading to the Rutherford model of the atom.
Bohr's theory suggests fixed orbits for electrons, while modern theory uses probability-based orbitals. If Rutherford's results had supported Thomson's model, most alpha particles would pass through gold foil with minimal deflection, indicating a uniform positive charge. Instead, Rutherford found particles scattered unexpectedly, revealing a dense nucleus in atoms.
;
