Bohr and Schrodinger Model

Difference Between Bohr and Schrodinger Model

Introduction of Bohr and Schrodinger Model

Niels Bohr’s 1913 Bohr Model offered one early attempt to explain atom structure. This model suggested that electrons orbited around their nucleus with fixed energy levels similar to planets around our sun; this approach successfully explained hydrogen’s spectral lines but couldn’t account for more complex atoms.

Erwin Schrodinger first introduced the Schrodinger Model into quantum mechanics during the 1920s as part of his general framework for understanding electrons as wave functions, with probability clouds representing their likely locations around nuclei.

Unlike Bohr’s Model, which only considered one-electron atoms, Schrodinger’s was applicable to multi-electron atoms allowing more accurate depictions of the structure and behavior of multi-electron atoms.

His model provided precise calculations of energy levels, chemical properties, and molecular structures transforming our understanding of microscopic reality.

Definition of the Bohr Model

Bohr Model
Figure 01: Bohr Model

Niels Bohr’s revolutionary Bohr Model, first proposed by Danish physicist Niels Bohr in 1913, marked a breakthrough in our understanding of atomic structure during early quantum mechanics studies. It attempted to explain electron behavior within an atom’s nucleus – particularly their emission and absorption of light rays.

Bohr’s model proposed that electrons orbited around a nucleus at specific energy levels or shells, similar to planets in our solar system. Bohr quantized this energy level so electrons could only occupy certain orbits with fixed energies.

When electrons moved from higher-energy orbits into lower ones they released light at specific frequencies, creating spectral lines; this provided an explanation for their observed line spectrums in hydrogen and other simple atoms.

Bohr’s revolutionary model provided insights into atomic phenomena that classical physics couldn’t explain, yet also had limitations; for instance, while it worked well to predict single electron systems like hydrogen’s behavior accurately, such as its properties being wave-like in nature and complicated interactions that occurred among multielectron atoms.

Therefore it serves as a transition between classical and quantum physics and opens the way to more comprehensive theories like the Schrodinger Model.

History of Bohr Model

Key factors leading to the creation of the Bohr Model include:

Scientists had discovered distinct spectral lines in the emission and absorption spectra of elements, traditional physics couldn’t explain why these occurred at certain frequencies; therefore presenting an obstacle that demanded a new theoretical framework.

  • Quantization of Energy: Classical physics suggested that electrons would continuously emit energy as they spiraled toward an atom’s nucleus, leading to instability. But this theory directly contradicted observed atom stability. Niels Bohr introduced quantized energy levels so electrons would exist only within specific orbits with discrete energies in order to minimize energy loss and instability. This concept prevented energy loss while maintaining stability.
  • Rutherford’s Nuclear Model: Following Ernest Rutherford’s discovery of an atomic nucleus, electrons appeared to orbit it, classic electromagnetic theory couldn’t explain why these electrons weren’t emitting radiation and collapsing inward due to acceleration.
  • Planck’s Quantum Theory: Max Planck’s work on quantized energy levels in blackbody radiation provided the basis for understanding energy quantization; his theories informed and inspired Bohr’s ideas regarding quantized electron orbits.
  • Hydrogen Spectrum: Bohr’s model successfully provided an explanation for these spectral lines by correlating them with transitions between different energy levels within an atom’s interior.
  • Scientists desired consistency: Scientists sought a model that would bridge the gap between classical and quantum physics, such as Bohr’s semiclassical approach that included quantized energy levels while maintaining some classical concepts as part of his model; Bohr was thus taking one step towards creating a full quantum theory.

characteristics of the Bohr Model of an Atom:

Here are a few key characteristics or features of the Bohr Model of an Atom:

  • Quantized Energy Levels: At the core of the Bohr Model lies electrons’ existence only within quantized energy levels around nuclei; these integer values represent these energy states (n= 1, 2, 3 etc.).
  • Stationary Orbits: According to Bohr’s Model, electrons could move around nuclei in stable circular orbits without emitting energy – these were called stationary orbits or allowed orbits.
  • Quantifying Angle Momentum (Quantification of Angle Momentum): This model introduced the notion that an electron’s angular momentum can only take on specific values based on Planck’s constant.
  • Energy Transitions: Electrons have the ability to transition between energy levels by either absorbing or emitting photons; when one moves down in energy level it emits light with specific frequencies forming visible spectral lines.
  • Bohr Model Explained Hydrogen Atom Emission/Absorption Spectrum Lines: The Bohr Model provided an effective explanation for hydrogen’s emission/absorption spectra with distinct energy transition lines; these corresponded with specific energy transition levels between different energy states in its emission/absorption spectra.
  • Limitations of the Bohr Model: Unfortunately, when applied to more complex atoms, the Bohr Model had its limitations. It couldn’t account for all the minute details of atomic structure and behavior in multielectron systems and it did not take into account their wavelike properties – an integral component of quantum mechanics later discovered through experimentation.
  • Hydrogen-Like Systems: This model’s accuracy was limited primarily to hydrogen-like systems consisting of atoms with one electron; for atoms containing multiple electrons it became less accurate.
  • Quantization of Energy Emission: The Bohr Model provided an explanation as to why certain frequencies of light are emitted or absorbed by atoms at certain wavelengths; linking this phenomenon with electron energy level transitions.

Definition of the Schrodinger Model

Schrodinger Model
Figure 02: Schrodinger Model

It is the Schrodinger Model, more commonly called”the Schrodinger Wave Equation or Quantum Mechanical Model is an important notion in quantum mechanics. It offers a more thorough and precise explanation of the behavior of electrons within the atom.

It was developed by Austrian scientist Erwin Schrodinger in the 1920s This revolutionary concept transformed our understanding of the microscopic world.

The Schrodinger Model relies on the particle’s wave-like nature. In order to represent this idea mathematically it is necessary to understand the Schrodinger equation is based on an equation that mathematically describes the movement of particles across space and time with its square employed as a predictor of the identification of a particle at a particular place.

Schrodinger Model electrons exist in areas of space that have different probabilities of finding them often called orbitals or electron clouds. The probability-based behavior of Schrodinger Model electrons is due to Heisenberg’s Uncertainty Principle in which it is claimed that the momentum and its location cannot be determined with precision simultaneously.

It is believed that the Schrodinger Model can explain a range of phenomena, like quantum energy levels, and the distinct lines that are visible in the atomic spectrum. Its application goes far beyond the single electron system and includes multielectron atoms because it is able to explain complicated interactions between electrons.

History of the Schrodinger Model

Schrodinger Model can be broken down into various causes that contributed to its formation:

  • Wave-Particle Duality: In the early 20th century, an idea emerged known as wave-particle duality which suggested that particles, like electrons, may exhibit properties that are both wavelike and particle-like – challenging traditional understandings about particle behavior while necessitating new theories to account for this new understanding.
  • Classical Model Failures: While the Bohr Model provided some insights into atomic structure, it failed to fully describe multi-electron electron behavior and finer specifics of spectral lines. Classical science could not account for complex interactions taking place at an atomic scale.
  • Louis de Broglie’s De Broglie Hypothesis: In this concept, Louis de Broglie postulated that electrons and particles could be classified as waves with particular wavelengths; this idea provided the basis for treating particles as waves for quantum mechanical purposes.
  • Quantum Mechanics Employs Wave Equations: Erwin Schrodinger, Max Born, and Werner Heisenberg were independently studying mathematical equations to describe particle-wave behavior; Schrodinger’s research led him to create the Schrodinger equation which would ultimately become part of quantum mechanics.
  • Scientists Theory: Scientists sought a comprehensive theory that could accurately describe particles exhibiting wave-like behavior, precisely establish energy and spectrum measurements of molecules, and transcend classical physics’ problems.

characteristics of the Schrodinger Model

  • Wave Function: Central to the Schrodinger Model is its notion of a wave function, which describes the behavior of particles such as electrons in terms of both time and space.
  • Probability Density: The square of a wave function indicates the probability density for finding particles at specific positions; this probabilistic interpretation marks a fundamental departure from classical physics.
  • Quantized Energy Levels: Similar to the Bohr Model, the Schrodinger Model also describes quantized energy levels within an atom’s nucleus by treating electrons as standing waves around it.
  • Orbitals: Electrons in the Schrodinger Model do not follow fixed orbits but rather exist within regions of space with differing probabilities of being found, known as orbitals or electron clouds.
  • Heisenberg Uncertainty Principle: The Schrodinger Model incorporates Heisenberg Uncertainty Principle, which states that there’s an inherent limit to our ability to know with complete accuracy both the location and momentum of a particle.
  • Applicability to Multi-Electron Systems: Unlike the Bohr Model, the Schrodinger Model can account for multi-electron atoms. It takes into account interactions among electrons which is essential in understanding atomic and molecular properties.
  • Wave-Particle Duality: The Schrodinger Model recognizes this duality between waves and particles by accepting that electrons exhibit both particle-like and wave-like behaviors.

Comparison  between the Bohr Model and the Schrödinger Model

Here’s a simplified comparison chart between the Bohr Model and the Schrödinger Model:

Aspect Bohr Model Schrödinger Model
Development Era Early 20th Century 1920s
Key Contributor Niels Bohr Erwin Schrödinger
Focus Energy levels, Spectral lines Wave functions, Probability distributions
Electron Orbits Fixed, circular orbits Electron clouds (orbitals)
Energy Quantization Quantized energy levels for electrons Quantized energy levels
Applicability Limited to hydrogen-like systems Applicable to all atoms
Interaction Limited interactions in single-electron atoms Considers interactions in multi-electron systems
Wave-Particle Duality Doesn’t fully embrace wave-particle duality Embraces wave-particle duality
Uncertainty Principle Doesn’t explicitly incorporate Incorporated through probabilistic nature
Multi-Electron Systems Inapplicable or limited accuracy Accurate description of multi-electron systems
Mathematical Framework Incorporates classical mechanics Based on quantum mechanics
Precision Limited accuracy for complex atoms Accurate predictions of atomic behaviors
Chemical Bonding Limited explanation of chemical bonding Offers insights into molecular structure
Significance Transitional model in atomic theory evolution Foundational in modern quantum mechanics
Current Usage Historical context Forms the basis of modern atomic theory
Technological Applications Limited impact Forms the foundation of modern technology

How each model treats various aspects

Electron Orbits:

  • Bohr Model: Electrons are treated as orbiting their nuclei in fixed circular orbits.
  • Schrodinger Model: Electrons can be represented using probability distributions or wave functions which outline regions with higher or lower probabilities of finding an electron.

Energy Levels:

  • Bohr Model: Electrons exist in quantized energy states and transitions between these levels explain spectral lines.
  • Schrodinger Model: Quantized energies can also be described using the Schrodinger equation and wave functions, creating quantized levels in space-time.


  • Bohr Model is limited to hydrogen-like systems and single electron atoms. For all other atoms including multielectron systems.


  • Bohr Model: Treats interactions in an overly simplified fashion, often neglecting them.
  • Schrodinger Model: Incorporates more complex interactions between electrons for more accurate descriptions of atom behavior.

Wave-Particle Duality:

  • Bohr Model Doesn’t Address it Directly Schrodinger Model Adopts Wave-Particle Duality by Treating Electrons As Both Particles and Waves

Mathematical Framework:

  • Bohr Model: Conjoins classical mechanics with quantization rules.
  • Schrodinger Model: Based upon quantum mechanical principles and wave functions described by Schrodinger Equation.


  • Bohr Model: The Bohr Model is less reliable for multi-electron systems and complex atoms.
  • Schrodinger Model: The Schrodinger Model offers highly accurate predictions for various properties and behaviors of atoms and elements.

Chemical Bonding:

  • Bohr Model:  Bohr’s Model of chemical bonding provides only limited explanation.
  • Schrodinger Model: The Schrodinger Model offers insights into molecular structure and bonding through electron behavior.

Technological Impact:

  • Bohr Model: Bohr Model has a limited impact on technology;
  • Schrodinger Model: The Schrodinger Model serves as the basis for various technological applications like semiconductors and lasers.


The Bohr and Schrodinger models provide two approaches to understanding electron behavior within atoms. Proposed by Niels Bohr, the former employs quantized energy levels and fixed electron orbits that explain the hydrogen spectrum well while being limited to single electron systems.

As an intermediate model bridging classical and quantum physics, it succeeded well enough at explaining hydrogen but had difficulty explaining complex systems and interactions.

Erwin Schrodinger developed the Schrodinger Model based in quantum mechanics to characterize electrons as wave functions, treating electron clouds or orbitals probabilistically with high probability regions for electron discovery.

It incorporates wave-particle duality, embraces the Heisenberg Uncertainty Principle, and accurately predicts energy levels, spectra, and other behaviors of atoms – unlike Bohr’s model it applies across all atoms including multielectron systems making it one of the cornerstone concepts in modern physics.