Chem 8.3 Discovering the Nucleus

Question 1

How did Rutherford test the plum pudding model?

Answer 1

He charged positively-charged alpha particles at a piece of gold foil, and if Thomson’s model was correct, most of the particles should g straight through the foil, while some may change direction slightly when passing close to a negatively-charged electron.

Question 2

Did Rutherford prove Thomson right or wrong?

Answer 2

Thomson was WRONG. Some alpha particles actually bounced back, meaning that the plum pudding model wasn’t correct.

Question 3

What was Rutherford’s new model?

Answer 3

The new atom model meant that atoms have a central nucleus, and most of the mass is present there with an overall positive charge.

The model explained that bounced particles had hit the nucleus; particles that shifted direction had touched the outside of a nucleus; and the particles that went straight through the foil passed by the empty space.