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random history facts about atomic physics
Who defined atoms to be “the smallest indivisible object”?
(this is a flat out lie btw)
When?
Democritos
~500 BC
Who
developed the cannonball model of the atom,
postulated all atoms of a given element are alike,
postulated atoms combine in definite proportions (C+2O=CO2)?
When?
J. Dalton
1803
Who postulated that different gasses with the same volume with the same volume, temperature, and pressure will have the same number of molecules?
When?
A. Avogadro
1811
Who did work with Crooke’s Tube and penetrating 😳 x-rays?
When?
W. Roentgen
~1845
Who
did work with Uranium ores,
found fogging on photographs in absence of light or electricity?
When?
H. Becquerel
~1845
Who did work with Thorium, Polonium, and Radium ores?
When?
M. Curie
~1845
Who developed the first periodic table?
When?
Mendelev
1869
Who
did research through Canvendish labs,
discovered the first fundamental particle, the electron,
determined the charge-to-mass ratio of an electron to be ~1.76×108 c/g,
estimated me to be ~10-3 mH?
When?
developed the plum pudding model of the atom?
When?
won the Nobel Prize for the discovery of the electron?
When?
J. Thompson
1897
1904
1906
Plum Pudding Model of the Atom
What were the pros of this model?
explained stable, neutral atoms
explained the origins of electrons and their properties
Plum Pudding Model of the Atom
What were the cons of this model?
couldn’t explain why some atoms are unstable
couldn’t explain spectral lines
couldn’t explain the scattering of charged particles
Plum Pudding Model of the Atom
What is the main feature of this model?
the stability of atoms
Who
did work to develop Avogadro’s number,
developed the photo-electron theory?
When?
A. Einstein
1905
Who developed the modern periodic table?
When?
Moseley
1913
Who
determined the charge-to-mass ratio of the electron to be 1.76z10 c/g,
determined the mass of the electron to be 9×10 g,
experimented with x-ray ionized air and oil droplets,
found a unique electron constant ~1.62×10 C,
When?
won a… Nobel Prize :D
When?
R. Millikan
1909
1924
Who determined Avogadro’s number to be 6.6×10 atoms/mole?
When?
J. Perrin
1909
Who were the first to do gold foil experiments?
When?
Rutherford and Geiger + Mardsen
1911
Who developed the planetary model of the atom?
When?
Rutherford
1911
Planetary Model of the Atom
What were the pros of this model?
explained gold foil experiments
explained alpha particle scattering
Planetary Model of the Atom
What were the cons of this model?
couldn’t explain why spectral lines appear as a continuum
didn’t answer what keeps protons together in the nucleus
Who developed the first quantum model of the atom?
When?
N. Bohr
1913
Quantum Model of the Atom
What are the main features of this model?
Quantum Model of the Atom
Note 
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