Dalton’s atomic model is one of the fundamentals of physics and chemistry. This theory of atomic composition was hypothesized and partially confirmed by the English chemist and Physicist John Dalton. Dalton came with his Atomic theory as a result of his research into gases. He discovered that certain gases only could be combined in certain proportions even if two different compounds shared the same common element or group of elements. Through deductive reasoning and experimentation, he made an interesting discovery. His findings led him to hypothesize that elements combine at the atomic level in fixed ratios. This ratio would naturally differ in compounds due to the unique atomic weights of the elements being combined.
This was a revolutionary idea but further experimentation by himself and others confirmed his theory. The findings became the basis of of Dalton’s Atomic Laws or Model. These laws focus on five basic theorems. First, Pure Elements consist of particles called atoms. Second,atoms of an element are all the same for that element. That means gold is gold and oxygen is oxygen down to the last atom. Third, atoms of different elements can be told apart by their atomic weights. Fourth, atoms of elements unite to form chemical compounds. Finally, atoms can neither be created or destroyed in chemical reaction. The grouping only changes.
The last of Dalton’s Atom Model were at the time considered true for all reactions involving atoms. This was later corrected with the discovery of nuclear fission and fusion. So we now know that this only holds true for chemical reactions.
Like other scientific theories, Dalton’s atomic model has been perfected over time with the research and discoveries of other scientists. We now know that the atom can be divided into even smaller particles and we have even discovered the actual internal atom structure, even able to view it through modern technology. We now know that atomic weight is a product of the structure of the atoms as well.
This atomic theory made possible modern chemistry and physics. Up until Dalton’s time the atom was only considered to a philosophical construct passed down by the ancient Greeks. Dalton’s ground breaking work made theory reality. This understanding the atom helped to fuel many other discoveries such as the fundamental forces and Einstein’s theory of relativity. It is especially is important when one goes into Quantum physics a discipline that looks at physics at the atomic and subatomic levels.
If you enjoyed this article there are others that you will enjoy on Universe today. There is an interesting article about the number or atoms in the universe. There is also an interesting article about dark matter.
There are also great resources on the web if you want to learn more about Dalton’s model. There is an article on the Central Queensland University that goes into detail about Dalton’s Atomic model. There is also a great article on the Clackham Community College website that simply explains the theory.
You can also check out Astronomy Cast. Episode 138 Quantum Mechanics talks in detail about Quantum physics.