# What are the main ideas of Dalton's atomic theory?

May 31, 2017

#### Explanation:

1. Matter was composed of small, indivisible particles called atoms.

2. Atoms of a given element are identical in size and mass and chemistry.

3. Atoms can neither be created nor destroyed.

4. Atoms combine in simple whole number ratios to form a variety of different chemical compounds.

5. Atoms are combined, separated, and rearranged in a chemical reaction.

None of these principles was revolutionary or even new. The idea of the $\text{atom}$, the small, fundamental indivisible particle, went back at least 2000 years. What separated Dalton from his predecessors was that he was a very accomplished experimentalist. He had made extensive studies of the behaviours and properties of different gases. He was able to interpret physical data on the basis of his laws, and he was also able to predict the likely results of new experiments.