John Dalton's Theory of the Atom

What was right? What was wrong?

Who was John Dalton?

John Dalton was an English educator, chemist, and scientist from the 18th and 19th century. He lived from 1766 to 1844. He studied meteorology and colorblindness, which made him very popular. He was the first modern day scientist to research and discuss the Atomic Theory.

His Five Facts About the Atom.

John Dalton deduced 5 facts about the atoms.

1. All matter consists of tiny particles.

2. Atoms cannot be destroyed or changed.

3. Elements are characterized by the mass of their atoms.

4. When elements react the atoms combine into whole number ratios.

5. Sometimes the elements would combine in different ways, sometimes creating new compounds.

What was Wrong with his Theory?

There were two flaws in Daltons Atomic Theory.

1. Atoms can be divided.

2. Not all elements have the same mass. These are called Isotopes.