The History of the Atomic Model: Heisenberg’s uncertainty principle


Now that the electron could be treated as a wave and as a particle, the work of Werner Heisenberg was important in quantifying this as a mathematical concept and furthering our understanding of the mysterious electron.

Heisenberg’s uncertainty principle followed the work of Albert Einstein and Max Planck in 1927. Heisenberg developed a mathematical way of expressing the energy levels of electrons in atoms.

His theory states that there is uncertainty in measuring such features of a particle as the position and momentum of an electron are hard to predict. His theory went further to also identify that the more precise the position of the electron the less precise the momentum would be.

This relates to the difficult in measuring the quantum values of an electron all at once and was the first time that a scientist had hypothesised that with the precise measurement of one value for example the momentum of the electron, then the position of the electron would be more unknown and less precise. His work evolved the understanding of wave particle duality as when treated as a particle we can easily measure the momentum of a particle but as it is spread out and moving we cannot predict its position. On the other hand, when treated as a wave we can predict the position of the electron wave but the momentum cannot be precisely measured.

Terms in section
Max Planck

Max Planck was a German physicist who discovered that energy that is emitted is released in small packets called quanta. He related the amount of energy released to the frequency of the wave.

Albert Einstein

Albert Einstein was a German physicist who was pivotal in many scientific discoveries in his life. He contributed to the field of chemistry through his work on the photoelectric effect and mathematics of the atom.


Werner Heisenberg was a German physicist who was a pioneer in the field of quantum mechanics. He devised the principle of uncertainty relating to the momentum and position of an electron.

Energy levels

Energy levels is the term used when treating electrons as waves/particles we can treat them as energy levels. The sub orbitals s p d and f are in ascending energy levels with electrons further away from the nucleus being in higher energy levels

Uncertainty Principle

Heisenberg’s uncertainty principle is used to describe the relationship between the momentum and position of an electron. Where by if the exact position of the electron is known the momentum will be uncertain.


The History of the Atomic Model: Wave Particle Duality


The History of the Atomic Model: Schrodinger and the Wave Equation