Development of the Atomic Model. 400 B.C. – Democritus He thought atoms were “un-cuttable” Also atoms are hard small particles.

Development of the Atomic Model

400 B.C. – Democritus

• He thought atoms were “un-cuttable”

• Also atoms are hard small particles

1808-Dalton

• He believed that all substances are made of atoms.

• Atoms of the same element are exactly alike, and with different elements are different.

• He made experiments in combining elements.

1897-Thomson

• The atomic structure was led to the plum-pudding model.

• Discovered the electron

• He made a cathode-ray tube experiment

1911-Rutherford • The electrons move in empty space in the

atom

• Discovered the nucleus

• Performed the gold foil experiment

• Inside are small negatively changed particles in a atom

1913-Bohr

• Electrons travel in definite paths; orbit the nucleus

• The electrons jump from path to path.

1926-Schrodinger

• The electrons path cannot be predicted

• The electrons are found in the electron cloud not paths

Word reminder

• Democritus- snowflake or popcorn .

• Dalton-ball

• Thomson-chocolate chip cookie

• Rutherford- sprinkle doughnut

• Bohr- plants

• Schrodinger-electron cloud

1)Who believed that the electrons were found in electron cloud ? 2) Who thought that jump from path to path?

1) A) Bohr

B) Schrodinger

C) Rutherford

D) Thomson

2) A) Bohr

B) Dalton

C) Democritus

D) Rutherford

1) Who believed that atoms are “uncuttable”?2)Who believed that atoms of the same element are exactly alike?

• 1) a) Dalton

b) Democritus

c) Thomson

d) Bohr

• 2) a ) Dalton b ) Bohr

c ) Rutherford

d ) no clue.

Thomson conducted what experiment?

• A) Experiment in combining elements.

• B) Gold foil experiment

• C) Cathode-ray tube

• D) Electron clouds

THE END (: