Dalton’s Atomic Theory

BY: Ali, Steph, Hunter, Victoria

Who is John Dalton?

• English Teacher

• Chemist in the early 1800’s

• Identified the hereditary nature of red-green color blindness

• Revealed concept of Partial Pressures

• Credited as the father of modern atomic theory

What are the 5 key points of his theory?

• 1. Elements are made of extremely small particles called atoms.

• 2. Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, and other properties.

• 3. Atoms cannot be subdivided, created, or destroyed.

• 4. Atoms of different elements combine in simple whole-number ratios to form chemical compounds.

• 5. In chemical reactions, atoms are combined, separated, or rearranged.

Experiments

• 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.

Theory in science timeline

• Created in 1803

• Dalton created his theory near the beginning of the science timeline

• Allowing other scientist to build on Daltons theory.

How did it hold?

• Many other chemists built off of his theory

• His theory is pretty close to what we know about atoms today.

• We know that atoms are small particles, they can’t be created or destroyed, they have chemical reactions, and they form chemical compounds. Dalton was the one who has discovered this.