Scientific Models of the Atom

Question 1

What was John Daltons atomic theory?

Answer 1

• That substances were made up of atoms, that were tiny, hard spheres.
• That each element had its own atoms that differed from others in masses.

Question 2

What did J.J Thompson discover?

Answer 2

Electrons

Question 3

What are the features of the plum pudding model?

Answer 3

The atom is a ball of positive charge with negative electrons embedded in it.

Question 4

What was Ernest Rutherford’s Gold Foil experiment?

Answer 4

An experiment designed to test the plum pudding model.
Positively charged alpha particles were fired at thin gold foil. Most alpha particles went straight through the foil, but a few were scattered in different directions.

Question 5

What did Ernest Rutherford discover following the Gold Foil Experiment?

Answer 5

• That the atom is mostly empty space- shown by the majority of the alpha particles passing through.
• That the mass of an atom is concentrated at a positively charged centre, the nucleus- the times the alpha particles deflected, being when the nucleus collided with the nucleus of the gold atoms.

Question 6

What are the features of the nuclear model?

Answer 6

• It has a small, dense, nucleus, where most the atoms mass is concentrated.
• It has electrons orbit around the nucleus.
• Most of the atom is empty space.

Question 7

What did Neil Bohr discover about the atom?

Answer 7

That electrons orbit the nucleus at fixed distances, in fixed energy levels, or shells.

Question 8

What are the features of Bohrs model of the atom?

Answer 8

• Positively charged nucleus.
• Electrons orbiting the nucleus in fixed
  energy levels, or shells,

Question 9

What did James Chadwick discover?

Answer 9

Neutrons

Question 10

How did James Chadwick discover the neutron?

Answer 10

He used a version of Rutherford’s experiment, using a sheet of beryllium and a paraffin block instead of gold foil. From this he discovered the proton-sized neutral particle - now known as the neutron.