Atomic Timeline

Democritous

440

A picture of Democritous.

Democritus

440

Sorry for the 440 AC. It would not let me make it 440 BC, so this is really suppost to be 440 BC
1. All substances are made of atoms
2. Atoms are made of a single material formed into different shapes and sizes
3. Atoms are small, hard particles
4. Figured that atoms are the smallest particle of matter
4. Atoms are "Uncuttable"

John Dalton

Jan 1, 1803

1. Atoms of different elements are different
2. Atoms of the same element are the same
3. He conducted experiments in combining elements
4. Wanted to know why elements combine in specific proportions
5. Compounds have a definate ratio
6. Atoms can't be made or destroyed in a chemical reaction

John Dalton

Jan 1, 1803

A picture of John Dalton.

J.J Thompson

Jan 1, 1897

1. There are small, negitively charged particles inside an atom
2. His theory of the atomic structure led to the "Plum-Pudding" model
3. He conducted the cathode -ray tube experiment

JJ Tompson

Jan 1, 1897

A picture of JJ Tompson.

Rutherford

Jan 1, 1909

1. Nost of an atom's mass is in the nucleus
2. He conducted the gold foil experiment
3. There is a small, dense, positively charged nucleus
4. Atoms contain mostly empty space

Rutherford

Jan 1, 1909

A picture of Rutherford.

Bohr

Jan 1, 1913

1. Electrons travel in certain paths, or energy levels
2. Electrons can jump from a path in one level to a path in another level
3. Electrons travel in planet like orbits

Bohr

Jan 1, 1913

A picture of Bohr

Schrodinger & Heisenberg

Jan 1, 1920

1. Electron paths cannot be predicted
2. Electrons travel in certain regions

Schrodinger

Jan 1, 1920

A picture of Schrodinger.

James Chadwick

Jan 1, 1932

1. Discovered another particle in the nucleus of atoms
2. Elecrons are found in electron clouds, not paths
3. Discovered the neutal Neutron
4. Advanced the work of nuclear fission and the Atomic Model

James Chadwich

Jan 1, 1932

A picture of James Chadwich.