history of the atom

Question 1

Democritus

Answer 1

First so have ideas about particles and atoms.

Question 2

John Dalton

Answer 2

• Didn’t think atoms could be divided or split; thought atoms rearranged themselves with other atoms.
• Each element had its own atoms that differed from others in their mass.
• Substances we’re made up of atoms that were tiny and spherical.

Question 3

J. J. Thompson

Answer 3

• Discovered the election.
• Said that the tiny negatively charged electrons must be embedded in a cloud of positive charge, known as the plum pudding model.

Question 4

Ernest Rutherford

Answer 4

-Electrons must be orbiting around the nucleus, which contains very dense positively charged protons.

Question 5

Niels Bohr

Answer 5

Suggested that elections must be orbiting the nucleus at set distances, in certain fixed energy levels (or shells).

Question 6

James Chadwick

Answer 6

-Discovered the neutron.