What is the main difference between the Schrödinger model and the Bohr atomic model?

The main difference between the Schrödinger model and the Bohr model of the atom lies in how they describe the behavior of electrons around the nucleus.

In the Bohr model, electrons are pictured as moving in fixed orbits around the nucleus, much like planets orbiting the sun. Each orbit represents a specific energy level, and electrons can only gain or lose energy by jumping from one orbit to another. This model was developed by Niels Bohr in 1913 and was successful in explaining the hydrogen atom spectrum, but it could not account for the spectra of more complex atoms or the chemical behavior of atoms.

On the other hand, the Schrödinger model, introduced by Erwin Schrödinger in 1926, uses quantum mechanics to describe the position and energy of electrons in an atom. Instead of fixed orbits, the Schrödinger model represents electrons as existing in clouds, or orbitals, that are defined by a mathematical function called a wavefunction. The wavefunction gives the probability of finding an electron in a certain region of space around the nucleus. This model allows for a more accurate and detailed description of electrons, and it can be applied to all atoms, not just hydrogen.

In summary, the Bohr model treats electrons as particles in definite orbits, while the Schrödinger model treats them as wave-like entities with probabilistic distributions.

Extra: The concepts in the Schrödinger and Bohr models are deeply rooted in the development of quantum mechanics. Bohr's model was an early attempt to incorporate quantum ideas into the atomic structure, proposing quantization of angular momentum, but it still kept one foot in classical physics. Schrödinger's model, however, is fully quantum mechanical, incorporating principles such as wave-particle duality and uncertainty.

The idea of wave-particle duality suggests that particles like electrons have properties of both particles and waves. In the context of the Schrödinger model, this means that the precise location of an electron cannot be determined at a given moment. Instead, we can only predict the probability of finding an electron in a certain area around the nucleus. This introduces a probabilistic nature to atomic physics, which is a fundamental departure from the deterministic approach taken by classical physics, as seen in the Bohr model.

Moreover, the Schrödinger equation, which is central to Schrödinger's model, is a complex equation that involves the wavefunction of an electron and is capable of describing the behavior of electrons in any atom. The solutions to the Schrödinger equation give us the possible energy levels of an electron and the shape of the orbitals where electrons have a high probability of being found. This has profound implications not just for atomic theory, but also for chemistry, as the shape and energy of the orbitals determine how atoms will interact and bond with each other.