How John Dalton came up with the Atomic Theory of Matter

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John Dalton investigated into the great depths of chemistry. He came up with a theory on the smallest particles in the universe, of what makes up what we call "matter". All matter consists of indivisible particles. Dalton gave the name to these minute particles, the atom.

There are different types of atoms, these are called elements. Hydrogen, oxygen and nitrogen are examples of elements. Each of these elements is different from one another only by its weight. Atoms of the same element all have the same mass. Atoms of different elements are different in mass. Dalton used symbols to represent the elements. He imagined atoms to be tiny spheres, thus to draw atoms would be to draw circles.

He used patterns within the circles to distinguish the different elements. Using this way to symbolize invisible atoms, he could experiment with their combining properties. He created a "Table of Atomic Weights" and using the information from this table, he placed them in a significant order determined by the weight of the elements, comparing them to hydrogen, the lightest element, which is number one on the table and has the atomic number of 1.

Dalton discovered the "Law of Multiple Proportions". This states that the weights of elements always combine with one another in ratios of small whole numbers. Dalton experimented with a gas called nitric oxide (NO) and oxygen (O). He reacted them together to produce a third type of gas. The results were determined by the proportions or ratios of the two reacting gasses.

2NO + O -> N2O3
NO + O -> NO2

Dalton carried out experiments like this, using the law of multiple proportions, and completed the table of atomic weights.

Dalton concluded on the discovery of atoms, the "Atomic Theory of Matter"

1. Matter consists of indivisible atoms.
2. All of the atoms of a given chemical element are identical in mass and in all other properties.
3. Different chemical elements have different kinds of atoms; in
particular, their atoms have different masses.
4. Atoms are indestructible and retain their identities in chemical
5. A compound forms from its elements through the combination of atoms of
6. Unlike elements in small whole number ratios, such as 1 to 1, 2 to 2, 2 to 3, and so on.

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