Atomic Theory - Review Sheet
You should understand the contribution of each scientist. I don't expect you to memorize dates,
but I do want to know what each scientist contributed to the theory.
Democretus - 400 B.C.
- theory that matter is made of atoms
Boyle 1622 -1691
- defined element
Lavoisier 1743-1797
- pioneer of modern chemistry (careful and controlled experiments)
- conservation of mass (understand his experiment and compare to the lab "Does mass change
in a chemical reaction?")
Proust 1799
- law of constant composition (or definite proportions)
- understand this law and relate it to the Hydrogen and Oxygen generation lab
Dalton 1808
- Understand the meaning of each part of Dalton's atomic theory.
- You don't have to memorize the five parts, just understand what they mean.
- You should know which parts we now know are not true (according to modern atomic
theory).
- black box model of the atom
Crookes 1870
- Crookes tube
- Know how this is constructed (Know how cathode rays are generated and what they are.)
J.J. Thompsen - 1890
- How did he expand on Crookes' experiment?
- discovered the electron
- negative particles in all of matter (all atoms)
- must also be positive parts
Lord Kelvin - near Thompsen's time
- plum pudding model
Henri Becquerel - 1896
- discovered radioactivity of uranium
Marie Curie - 1905
- received Nobel prize (shared with her husband Pierre Curie and Henri Bequerel) for her
work in studying radiation.
- Name the three kinds of radiation and describe each type.
Rutheford - 1910
- Understand the gold foil experiment
- How was it set up?
- What did it show?
- Discovered the proton
- new model of atom (positively charged, very dense nucleus)
Niels Bohr - 1913
- Bohr model of the atom
- electrons in specific orbits with specific energies
Modern version of atom - 1950
- similar nucleus (protons + neutrons)
- electrons in orbitals not orbits
Understand isotopes, atomic mass, mass #, atomic #, ions
