Chem H Ch2 Important Figures

Question 1

Democritus

Answer 1

Believed that there was a smallest particle–“atomos”(uncuttable)– that made up all of nature

Question 2

John Dalton

Answer 2

Pioneered the organized atomic theory in the early 1800s. He also discovered the Law of Multiple Proportions.

Question 3

Joseph Proust

Answer 3

Discovered the Law of Constant Composition AKA the Law of Definite Proportions

Question 4

Antoine Lavoisier

Answer 4

Discovered the Law of Conservation of Mass

Question 5

J.J. Thomson

Answer 5

Credited with the discovery of the Electron.

Also theorized the “plum pudding” model of atoms. It featured a positive sphere of matter with negative electrons embedded in it.

Question 6

Robert Millikan

Answer 6

Determined the charge of the electron in 1909.

Created the Oil-Drop experiment

Question 7

Henri Becquerel

Answer 7

Henri was the first to observe radiation.

Its discovery showed that the atom had more subatomic particles and energy associated with it.

Question 8

Marie and Pierre Curie

Answer 8

Heavily studied radioactivity.

Question 9

Ernest Rutherford

Answer 9

shot alpha particles at a thin sheet of gold foil and observed the pattern of scatter of the particles. GOLD FOIL EXPERIMENT