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23 Cards in this Set
- Front
- Back
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Democritus
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proposed the first idea of the atom around 430 b.c. substances are made up of tiny, indestructable, indivisible, particles called "atomos" (philospher)
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John Dalton
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Proposed the first atomic theory in 1803
*all matter is made of indestructable invisble particles *All atoms of the same element are the same *all atoms of different elements are different *atoms combine in simple whole # ratios to form compounds |
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Lavoisier
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1788 Law of Conservation of Mass: Mass cannot be created or destoryed only rearranged
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Proust
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1794 Law of Definite Proportions: A pure substance always contains the same elements combined in the same proportions by mass (water always h2o)
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Dalton Law of multiple proportions
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the same two elements can combine in different ratios to form different compounds and the ratios to different compounds and the ratio of the masses of the 2nd element combines with a fixed mass of the 1st element is always a ratio of small whole #
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Gay-Lussac
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1804 Law of Combining Volumes: at constant temp. and pressure volumes of reacting gas and gaseous products are in small whole # ratios
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Avogadro
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Avogadro's Hypothesis: Equal volumes of gas under the same conditions have the same # of particles
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JJ Thomson
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1897 used cathode ray tubes to discover the electron and proton(chocolate chip cookie model)
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Robert Milikan
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1911 performed "oil drop experiment" to determing the charge of an electron
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James Chadwick
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1937 Berryllium bombared with alpha particles; revised theory to say atoms are not indestrucatble but made up of small particles
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Henry Mosley
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Used x-rays experiments to discover the atomic number of an element
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Henri Becquerel
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1896 discovered that uranium ores emit radiation resembling x-rays and that it exposed film
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Marie and Piere Curie
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1900 isolated two new elements; polonium and radium from uranium
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Ernest Rutherford
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studied radiation emitted by the substances especially alpha particles. Directed gold foil experiemnt, found the nucleus
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Einstein
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1905 famous equation E=mc2 shows that a small amount of mass can be converted into tremendous amounts of energy during a nuclear reaction.
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Neil Bohr
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1913 another assistant of Rutherford imprved the atomic model by attempting to answer the question of why electrons are not pulled into the nucleus
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Quantum Model
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positive core with an electron cloud surrounding it
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Quantum Theory
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Bohr based his atomic model on this, proposed by max plank in 1900. Energy is not emitted continuously but in small packets called quantia
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Spectroscopy
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the method of studying the interaction between matter and electromagnetic radiation
types:radio, micro, infrared, ultraviolet, x-rays, gamma rays |
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Principal Quantum
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Distance from the nucleus (n) always less than 7
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Second Quantum number
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sublevel/shape (l=n-1)
s=sphere p=peanut s 0 n=1 p 1 n=2 d 2 n=3 f 3 n=4 |
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Third Quantum Number
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(M) orbital/ direction
only 2 electrons can occupy an orbital at a time s-1 p-3 d-5 f-7 |
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Fourth Quantum Number
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(S) spin of electron (+-1/2)
(clockwise or counterclockwise) |
