The History of the Atom

Practice flashcards covering the timeline and key scientists in the history of atomic theory, including Democritus, John Dalton, J.J. Thomson, and Sir Ernst Rutherford.

Who was the Greek philosopher around 400 BC who first used the term 'atom'?

Democritus

What is the meaning of the Greek word 'atomos'?

Indivisible

According to Democritus's theory of the universe, what exists between atoms?

Empty space

In Democritus's model, how do atoms of different substances differ from each other?

They are different in size, weight and shape.

What atomic model did John Dalton propose in 1808?

Solid Sphere

According to John Dalton's theory, what happens when atoms of different elements combine?

They form compounds.

What are two properties of atoms identified in Dalton's model regarding their creation and division?

Atoms are indivisible and cannot be created or destroyed.

Which scientist proposed the 'Plum-pudding model' in 1904?

J.J. Thomson

How did J.J. Thomson describe the structure of the atom in his model?

A sphere of positive charges with negatively charged electrons embedded in it.

Why is an atom considered electrically neutral according to J.J. Thomson?

Because the positive charges and negative charges are equal.

Which scientist conducted an experiment using gold foil to prove or disprove Thomson's atomic model?

Sir Ernst Rutherford

In the experiment equipment mentioned for Rutherford's study, what was the purpose of the lead box and the fluorescent screen?

The lead box was used to hold the particles and the fluorescent screen was used to observe the result of the particles hitting the foil.