-
Period: 500 BCE to
Atomic Theory
-
400 BCE
Democritus
Atoms are "uncuttable".
Atoms are small, hard particles.
Atoms constantly move -
400 BCE
Democritus Atom
-
John Dalton
All substances are made of atoms.
Atoms of different elements are different.
Atoms of the same element are exactly alike.
Elements combine in specific proportions.
Conducted experiments in combining elements. -
Dalton Atom
-
J.J Thomson
Conducted the cathode-ray tube experiment.
Theory of the atomic structure lead to "plum pudding model".
There is a small, dense, negatively charged particles inside an atom. -
J.J Thomson Atom
-
Ernest Rutherford
Atoms mostly contain empty space.
Electrons move in empty space in the atom.
He conducted the gold foil experiment .
Most of an atom's mass is in the nucleus.
There is a small, dense, positively charged nucleus. -
Rutherford Atom
-
Niels Bohr
Electrons jump between levels from path to path.
Electrons travel in definite path. -
Bohr Atom
-
Schrodinger and Heisenberg
Electron paths can not be predicted.
Electrons are found in electron clouds, not paths. -
Schrodinger and Heisenberg Atom
You are not authorized to access this page.
