The scientists who contriubted to the discovery of the atom include: Democritus, John Dalton, J.J. Thompson, Rutherford, and Chadwick. All of their ideas came together and created what we call the atom.
-Democritus- was the first to come up with the term "atom". He stated that matter consisted of tiny particles that he named atom which comes from two Greek words meening invincible.
- John Dalton- conducted a series of expirements and realized that these "atoms" had a definite composition by weight. Dalton then came up with a theory:
Dalton’s Atomic Theory
1. All matter is composed of very small indivisible particles called atoms
2. Atoms of the same element are alike in weight and other properties. Atoms
of different elements are different in weight and other properties.
3. Compounds are formed by the union or separation of definite numbers of atoms
4. Atoms do not divide in chemical reactions; only whole atoms unite with other atoms.
Dalton combined his studies with another chemist named Proust to come up with the Law of Definite Proportions. Dalton’s Theory also proves the law of conservation of mass which had previously been stated by Lavoisier.
- J.J. Thompson: discovered the electron in 1895.
- Chadwick: discovered the neutron.
- Rutherford: discovered the proton.
-Bohr helped discover one of the three atomic models along with Rutherford and J.J. Thompson.

The difference between all of these scientists was that they were all aiming for different goals; however, they had to find new discoveries based on ones already found. For example, using the Gold Foil experiement and experiments conducted by Lavosier, they were able to come up with 3 atomic models. This was very impressive because the microscope was not yet invented and the atom is not able to be seen with the human eye.
The place in which each of these scientists grew up and were raised has no effect on the discoveries that they made. One could come from a poor family living on a farm which much of the scientists mentioned above did, but that did not stop them from making one of the biggest discoveries in the world.

The atomic theory is only a theory, and not a law because it has not been proven correct every single time that it has been tested. Atoms are indivisible under a nuclear change and the results vary. New discoveries state that on a smaller scale the atomic nucleus is being studied in order to determine the details of its structure and to develop sources of energy from nuclear fission and fusion, for the atom is not at all indivisible, as the ancient philosophers thought, but can undergo a number of possible changes.

It is important that we understand the structure of the atom becuase it will enable us to know more about the world around us and to come up with new inventions such as the atomic bomb and many more.