The Contributions of Neils Bohr to Chemistry

Niels Bohr was the brilliant Nobel Prize winning physicist who helped the world understand quantum mechanics.  His genius helped unlock the secrets of the atom; however, Bohr’s contribution influenced more than physics. His work was also crucial to physics’ sister science of chemistry. 

From Philosophy to Physics

Niels Bohr was born in 1885 at a time when there were revolutionary advances in the sciences.  Raised in a family of academics, Bohr benefited from asking questions and learned about the importance of experimentation. In 1905, barely 20 years old, Bohr conducted a series of experiments on the cohesion properties of liquid molecules. For his experiment, Bohr won an impressive prize and decided to puruse a career in physics and not philosophy.

Early Work

By 1911, Bohr completed his doctorate at University of Copenhagen and became a post-doctoral student at Cambridge. While at Cambridge, Bohr first conducted experiments under the guidance of Sir Joseph John Thomson, Nobel Laureate and discoverer of the electron and of isotopes. Later, Bohr would further his studies under the supervision of Ernest Rutherford, Nobel Prize winning chemist and discoverer of the proton.

Through the influence of these trailblazers, Bohr began considering the structure of atoms.  The electron, proton and the atomic nucleus were known.  Not yet 30, Bohr published his theory on the model of atomic structure in 1913.  Bohr theorized that electrons travel in orbits around the nucleus.  Visualize an atomic sized solar system. This was different from prior ideas about the structure of atoms.  Bohr also theorized that electrons could drop from higher to lower orbits and emit energy in the form of photons.  Bohr’s model considered the teaching of his mentors and the new age ideas of Einstein and Max Planck.

Bohr’s Atomic Model considered the following:

1. that electrons revolve in stable orbits and that those orbits they have a specific angular momentum which can be quantified by speed, orbit and mass;

2. that, while in their stable orbits, electrons do not radiate energy;

3. that when energy is introduced, an electron leaves its orbit, even if momentarily, and emits energy. This temporary state is called the excited state. And, the energy emitted is in the form of electromagnetic waves.

Several factors came from this theory including Bohr’s frequency and quantification conditions.  The model also explained Ryberg formula for atomic hydrogen spectral emissions.  

For this pioneering work, Bohr earned the 1922 Nobel Prize in Physics.  Bohr’s contribution was two-fold because not only did his work transform views on atomic structure. It also let the world better understand that atoms radiate energy.

Bohr’s Contribution to Chemistry

Bohr’s work clarified the model of the atom and allowed scientists to figure out a more accurate model for hydrogen.  It also explained energy emissions during chemical reactions and the rationale behind radiation.  His work continued in atomic theory where he and physicist John A. Wheeler devised the theory of atomic fission. With a clear view on the structure of atoms, scientists could better predict the physical properties of molecules and compounds.

Chemistry and Physics are linked.  While both deal with the nature of matter and energy, chemistry deals more with the interactions of atoms and their reactions in chemical processes.  Niels Bohr’s work made it easier to understand how atoms chemically react and for his pioneering work, he should also be considered an icon of chemistry.

For more information about the life and works of Niels Bohr, the library and local bookstores have a number of great books.  The web also has some great resources, check out the following websites: