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Atomic Theory Timeline - Coggle Diagram

- - - - Using that same logic, Aristotle thought matter could only have 4 properties: hot, cold, wet, and dry.
      - He believed that all things were made up of a specific combination of these 4 elements.
    - - Used his experiments and other people's experimental data to get to his conclusion.
      - 1896 - Antoine Henri Becquerel
        
        French physicist
        
        1897 - Thomson
        
        1908 - Rutherford
        
        Did an experiment to prove that atoms are not "puddings" filled with positive material (defying Thomson), using positively-charged particles fired at gold foil.
        
        1913 - Bohr
        
        Improved the atomic model
        
        Said that the mass was mostly in the nucleus of an atom.
        
        Electrons only exist in certain energy states
        
        Planetary Model
        
        1 more item...
        
        1926 - Schrodinger
        
        Quantum mechanics
        
        1 more item...
        
        Cloud Model
        
        3 more items...
        
        1964 - Murray Gell-Man & George Zweig
        
        5 more items...
        
        Slight revision of Bohr's model
        
        Bright-Line Spectrum
        
        Attempted to define the specific colors in hydrogen's spectrum
        
        Stated that atoms have a small, dense positively charged center, the "nucleus". With electrons scattered outside the nucleus, the atom was open spaced, making the center tiny.
        
        Said that the nucleus had a positive charge
        
        Analogy: Cherry with a pit (nucleus)
        
        Plum Pudding
        
        Atoms were made of a positive substance with negatively-charged particles (electrons) scattered inside.
        
        Electrons (plums) scattered in the positive sphere (pudding)
        
        Cathode Ray Tube Experiments
        
        First one to say that atoms are made of even smaller particles and discovered the electrons.
        
        Discovered the presence electrons in atoms
        
        Discovered radioactivity in Uranium
        
        Like Thomson's discovery of electrons, this made a lot of scientists rethink the atomic theory and atomic structure
        
        Spontaneous bursts of radioactivity from the nucleus.
        
        Becquerel's Atomic Model
        
        He found out that there were three types of radioactive substances: Positive (alpha), Neutral (gamma), and Negative (beta).
        
        He found this out by experimenting putting different types of radioactive substances in a magnetic field, and observing that they reacted differently by deflecting to different directions or not deflecting at all.
      - English school teacher.
      - Billiard Ball Model:
        
        He connected atoms and billiard balls and made the analogy that both were solid, spherical, and indestructible. He used wooden pool balls to model atoms.
        
        Analogy: Billiard ball
    - - This meant that his teachings set back advancements in chemistry knowledge for almost 2000 years! Analogy: graveyard
    - - Because of his large popularity, he caused Democritus' idea to be neglected for 2000 years!