History of Atoms

Question 1

Democratus

440 BCE

Answer 1

Atoms are tiny particles varying in size and shape

Question 2

John Dalton

1808

Answer 2

Compunds are combinations of different atoms

Question 3

J.J. Thompson

1897

Answer 3

A positivly charged unform area contains electrons dispersed within it (cookie model)

This was the discovery of the electron

Question 4

Ernest Rutherford

1911

Answer 4

Atoms are mostly empty space. Electrons are dispersed (not in rings) around a central nucleaus that contains most of the mass of the atom

Discovered Nucleas + Empty Space

Question 5

Niels Bohr

1913

Answer 5

Electrons orbit the nucleus in fixed levels (in shells)

Question 6

James Chadwick

1932

Answer 6

The nucleus contains not only positivly charged protons, but neutrons which hold the nucleus together

Discovered Neutron