What is the Difference Between Bohr and Schrodinger Model

Atoms are tiny building blocks of matter. Scientists use atomic models to depict these atoms and to study their behaviour. Bohr and Schrodinger models are two such models explaining an atom’s nature.

What is the difference between the Bohr and Schrodinger model? In the Bohr model, electrons are pictured like planets orbiting the nucleus in fixed, circular paths or energy levels, whereas in the Schrodinger model, electrons are described by wave functions (probabilities) instead of fixed paths.

Key Areas Covered

1. What is Bohr Model
      – Definition, Features 
2. What is Schrodinger Model
      – Definition, Features 
3. Similarities Between Bohr and Schrodinger Model
      – Outline of Common Features
4. Difference Between Bohr and Schrodinger Model
      – Comparison of Key Differences
5. FAQ: Bohr and Schrodinger Model
      – Answers to Frequently Asked Questions

Key Terms

Bohr Model, Schrodinger Model

What is the Bohr Model

Bohr’s model was proposed by Neils Bohr, introducing the idea of quantized energy levels. According to Bohr’s model, the nucleus in the atom is small and positively charged. Around the nucleus, there are electrons revolving around. Bohr proposed that these electrons are confined to specific allowed paths called orbits or shells. Each of these orbits has a fixed energy level. Electrons in the outermost shells have the highest energy. They are loosely bound to the nucleus. The electrons that are closer to the nucleus are tightly bound and have lower energy. However, there are no electrons in between energy levels.

In a stable state, electrons exist at the lowest energy state which is called the ground state. When an external energy source excites an electron, it goes to the higher energy levels above the ground state. Inversely, when an electron in a higher energy level comes back to a lower energy level or to the ground state which is more stable, it loses energy. This energy is emitted in the form of light. This is the reason behind specific colours emitted by atoms.

Bohr’s model successfully explains the atomic spectra of hydrogen. However, it fails to explain the behavior of more complex atomic spectra. In fact, it could not even explain the periodic table pattern.

What is the Schrodinger Model

The Schrodinger model was developed by Erwin Schrodinger and introduced the concept of wave mechanics. This model considers electrons not as tiny particles following precise paths but rather as wave functions that describe the probability of finding an electron in a certain region around the nucleus.

Electrons’ location is described by orbitals in the Schrodinger model, unlike fixed orbits in Bohr’s model. Orbitals are three-dimensional, where the ability to find an electron is higher, forming an electron cloud around the nucleus. These electron clouds contain denser areas where an electron could be found with the highest probability.

There are complex mathematical equations associated with these wave functions. These equations consider factors like the electron’s energy, angular momentum, and magnetic properties.

Schrodinger’s model is capable of explaining the electron behavior of atoms having more than one electron. It accounts for the filling of orbitals by electrons following specific rules, hence explaining the structure and patterns in the periodic table. However, though the Schrodinger model contains advancements, it does not give a final picture of the atom’s structure.

Similarities Between Bohr and Schrodinger Model

1. Both depict a central, positively charged nucleus.
2. Both models acknowledge that electrons occupy specific energy levels within the atom, not existing in a continuous range of energies.

Difference Between Bohr and Schrodinger Model

Definition

• The Bohr Model describes the atom with electrons orbiting the nucleus in fixed energy levels, while the Schrödinger Model describes the atom using wave functions to predict the probability distributions of electrons in orbitals.

Path of Electrons

• In Bohr’s model, electrons travel in fixed circular orbits around the nucleus. In Schrodinger’s model, electrons do not have definite paths. They exist in orbitals, regions where the probability of finding an electron is high.

Orbits

• Bohr model has circular orbits of specific radii. However, the Schrodinger model has orbitals in various 3D shapes depending on the electron’s energy level and angular momentum. These shapes are called s, p, d, and f orbitals.

Quantum Number

• In the Bohr model, only one quantum number (n) was used to define the electron’s energy level and orbit size. Meanwhile, in the Schrodinger model, three quantum numbers (n, l, m) are needed to describe the electron’s energy, orbital shape, and orientation in space.

Complexity

• Schrodinger’s model was much more complex than Bohr’s model.

Conclusion

Bohr and Schrodinger models depict the structure of atoms in different levels of understanding. Bohr’s model mainly describes fixed orbits where electrons travel, while Schrodinger’s model explains orbitals where the probability of finding an electron is high. This is the basic difference between Bohr and Schrodinger model.

FAQ: Bohr and Schrodinger Model

1. What is the difference between the Bohr orbit and the Schrödinger orbital?

Bohr’s orbits are definite paths for electrons, like planets around the sun. But Schrödinger orbitals are probability clouds. They show areas where you’re more likely to find the electron.

2. What is the biggest difference between Bohr’s model and the orbital model?

Bohr’s model depicts electrons in fixed, circular orbits. It’s like planets around the sun. However, orbitals exist in Schrodinger model where the probability of finding an electron is maximum.

3. What do you notice is the main difference between the Bohr model and the quantum model?

The biggest difference between the Bohr model and the quantum model is electron location. Bohr’s model has fixed orbits. The quantum model uses orbitals showing probability zones for electrons, not exact paths.

4. What are the limitations of the Schrodinger equation?

Schrödinger equation struggles with complex systems, even though it is ideal for single electron atoms. It also doesn’t handle relativity well, requiring different equations for high-speed particles.

5. Which model is more accurate, Bohr’s model or quantum model?

The quantum model, also known as the orbital model, is more accurate. While Bohr’s model explains basic atomic structure, it can’t handle complex atoms. The quantum model is more accurate in predicting the behavior of elements.

6. Why do we use the Bohr model instead of the quantum model?

We use Bohr’s model instead of the quantum model because it is relatively simple to use and understand at the beginner level. However, it’s important to note that the Bohr model cannot explain complex atomic structures.

Reference:

1. “Schrödinger Equation.” Wikipedia. Wikipedia Foundation.
2. “Bohr Model.” Wikipedia. Wikipedia Foundation.

Image Courtesy:

1. “Schrodinger model of the atom” By John Trombley – Own work (CC BY 4.0) via Commons Wikimedia
2. “Bohr’s model” By Sharon Bewick (CC BY-SA 3.0) via Commons Wikimedia