Who First Proposed the Atomic Theory?


Vincent White

The atomic theory is one of the most significant theories in the field of science, which explains the nature of matter. It proposes that all matter is made up of small, indivisible particles called atoms.

But who first proposed this theory? Let’s delve into the history and find out.

The Early Notions of Atom

The concept of atom has its roots in ancient Greece. Great philosophers like Democritus and Leucippus proposed that matter is made up of tiny, indivisible particles called atoms. However, their ideas were not widely accepted and were overshadowed by Aristotle’s theory of matter.

John Dalton

John Dalton is considered as the father of modern atomic theory. In 1803, he proposed that all elements are composed of atoms, which are unique to each element. He suggested that these atoms combine in fixed ratios to form compounds.

Dalton also introduced the concept of atomic weight and explained how it could be used to determine the ratio in which elements combine to form compounds. His work laid the groundwork for further research into atomic structure.

J.J. Thomson

In 1897, J. Thomson discovered electrons using a cathode ray tube experiment. He proposed that an atom consists of a positively charged sphere with electrons embedded within it like raisins in a pudding.

This model became known as the Plum Pudding Model or Thomson Model and was widely accepted until further research revealed its flaws.

Ernest Rutherford

Ernest Rutherford’s gold foil experiment in 1911 provided evidence for a new model of atomic structure. He discovered that atoms have a small, dense nucleus at their center surrounded by negatively charged electrons orbiting around it.

This model became known as the Rutherford Model or Nuclear Model and laid the foundation for further research into subatomic particles.

Niels Bohr

In 1913, Niels Bohr proposed a new model of atomic structure that incorporated quantum mechanics. He suggested that electrons orbit the nucleus in fixed energy levels or shells, and can jump from one shell to another by absorbing or emitting energy.

This model became known as the Bohr Model and is still used today to explain the behavior of electrons in atoms.


The atomic theory has come a long way since its inception in ancient Greece. From Democritus’ ideas to modern-day quantum mechanics, scientists have made significant contributions to our understanding of atomic structure. John Dalton, J. Thomson, Ernest Rutherford, and Niels Bohr are just a few of the many scientists who have played a vital role in shaping our current understanding of atoms and their behavior.


  • https://www.britannica.com/science/atom
  • https://www.livescience.com/37115-atomic-theory.html
  • https://www.thoughtco.com/history-of-the-atomic-model-373316