Chemistry Mini-project



400 B.C.

Democritus asked could atoms be cut in half. He later discovered they could not be cut. He though an atom looked like a round sphere

John Dalton

1800 - 1809

Dalton proposed that all matter was composed of atoms, indivisible and indestructible building blocks. He used other scientist information to get his results. He led the experiment leading to the acceptance of the atom.

Robert Millikan


Millikan performed an oil drop experiment that helped to quantify the charge of an electron

Ernest Rutherford

Approx. 1911

Rutherford was the first to discover that atoms have a small charged nucleus surrounded by largely empty space

Niels Bohr

1920 - 1930

Bohr created the Bohr Model. It shows the atom as a small, positively charged nucleus surrounded by orbiting electrons.

Werner Heisenberg


He developed the matrix mechanics formula

Erwin Schrodinger


Schrodinger used mathematical equations to describe the likelihood of finding an electron in a certain position.

James Chadwick


Chadwick discovered the neutron in atoms.