Atomic Theory and Key Scientists

Front

Who developed the atomic theory?

Back

John Dalton

Front

What year did John Dalton publish his atomic theory?

Back

1808

Front

What did J. J. Thomson's experiments provide evidence for?

Back

Atoms are made up of even smaller particles.

Front

What are the negatively charged particles discovered by J. J. Thomson called?

Back

Electrons

Front

How did Thomson describe the structure of an atom?

Back

As a positive sphere with electrons mixed through it.

Front

What are the four main ideas of Dalton's theory of the atom?

Back

1. All matter is made up of atoms. 2. Atoms cannot be created, divided, or destroyed. 3. All atoms of a certain element are identical. 4. Atoms join with other atoms to make new substances.

Front

How does Dalton's theory differ from the ideas of Democritus and Aristotle?

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Dalton's theory was based on evidence from experiments.

Front

What is an example of atoms combining to form a new substance?

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An oxygen atom combines with two hydrogen atoms to form water.

Front

What is the significance of Dalton's atomic theory?

Back

It marked the start of the modern theory of the atom.

Front

What did Rutherford’s experiment suggest about the structure of the atom?

Back

That atoms have a small, dense, positively charged nucleus.