chemistry unit 2 history of atoms

discovered the existence of atoms

democritus

the theory that elements are made of tiny unbreakable particles called atoms

dalton

theory that all atoms of the same element are identical

dalton

atoms form compounds

dalton

chemical reactions involve rearrangement of atoms not changes in the atoms themselves

dalton

created periodic table

mendeleev

first discovery of subatomic particles: the electron(negative charge)

thomson

cathode ray tube experiment

thomson

plum pudding model

thomson

discovered nucleus and that it holds the positive charges

rutherford

gold foil experiment

rutherford

discovered the atom is mostly empty space

rutherford

electrons circle nucleus in a fixed orbit

bohr

planetary model

bohr

discovered quantum model, shows that electrons orbit the nucleus in random patterns

schrodinger

discovered the neutron

chadwick