8.3 Discovering the nucleus

What did scientists want to know about Thomson's plum pudding model?

• How electrons are arranged in a positively-charged sphere.

• How protons and electrons interact.

• How negatively-charged electrons were discovered.

• How positively-charged particles behave in a vacuum.

Where did Ernest Rutherford move to in 1895 to study under Thomson?

• New Zealand.

• Cambridge, England.

• Montreal, Canada.

• Manchester, England.

What did Rutherford predict would happen if the plum pudding model was correct?

• Positive particles would go straight through the foil.

• Positive particles would bounce off the foil.

• Positive particles would change direction slightly.

• Positive particles would interact with negative electrons.

Who did Rutherford work with to test his prediction?

• James Chadwick and Niels Bohr.

• Hans Geiger and Ernest Marsden.

• Thomson and Rutherford.

• Geiger and Marsden.

What did Rutherford use to test the plum pudding model in 1909?

• Gold foil.

• Positively-charged particles.

• A fluorescent screen.

• All of the above.

How many positive particles bounced backwards off the foil during the experiment?

• None.

• About one in every 10,000.

• About half of them.

• All of them.

What did Rutherford conclude when his prediction was proven wrong?

• The plum pudding model must be correct.

• The plum pudding model must be wrong.

• More evidence is needed to make a conclusion.

• Thomson's model is outdated.

What did Rutherford's new model of the atom include?

• Central positive nucleus with empty space around it where electrons move.

• Central positive nucleus with empty space around it where neutrons move.

• Central negative nucleus with empty space around it where protons move.

• Central negative nucleus and empty space around it where protons move.

How did Rutherford explain the observations of Geiger and Marsden?

• Positive particles bounced off the nucleus.

• Positive particles passed through empty space.

• Positive particles interacted with electrons.

• Positive particles changed direction slightly.

Who suggested that electrons move in orbits or shells around the nucleus?

• James Chadwick.

• Niels Bohr.

• Thomson.

• Rutherford.