Semester I Exam Review NEW Flashcard



Matter is composed of small indivisible particles called ATOMS (Billiard ball model). These particles always combined in whole number ratios.




1st periodic table arrangement in “grid” format.
Arrangement was by WEIGHT.



Inventor of the SPECTROSCOPE.  Identified 3 types of spectra:  Continuous, Emission (or bright line), and absorption.



Used a highly modified cathode ray tube to discover the ELECTRON.  (see diagram below)

Measured the RATIO of mass to charge in an electron.



Gold foil experiment. First to experiment on the structure of the atom.


A = Hard impenetrable center called the nucleus.
B = Atom is mostly empty space
C = Nucleus has a (+) charge, same as an alpha particle



Added the concept of 7 ENERGY LEVELS to the Rutherford solar system model of the atom. Also explained Bright-line & absorbtion spectra by electrons changing energy levels as atoms absorb and emit light energy.



Uncertainity Principle. The exact position of an electron cannot be known all the time, due to the electron size and speed. Beginnings of the statistical model of the atom. 


 Also was leader of the Nazi project to construct an atomic weapon during WWII.


Developed the statistical model of the atom to include areas of high electron probability called ORBITALS.






Exclusion principle (2 electrons maximum per orbital shape…) and the concept of electron spin or full -vs- partial orbitals.
OIL DROP EXPERIMENT: which measured the values for the mass and charge of the electron.



Hund’s Rule:  Orbitals are created before they are filled…





Pudding Cake” or “Raisin Bun” model of the atom.  The atoms were solid, but had electrons embedded in them (like fruit in a fruit-cake).

Rearranged the modern Periodic Table based on the element’s atomic number.





Photoelectric effect experiment proving light could act as a particle (1st solar cell)




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