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Atomic Theory: Dalton → Thomson → Millikan � ...

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  • What did all four scientists ultimately show about atomic models?
    They are guesses
    They improve as new evidence appears
    They never change
    They are all correct
  • What evidence showed Thomson that the particles in the cathode ray had mass?
    They bounced off the tube walls
    They cast a shadow
    They traveled in circles
    They emitted light
  • Which part of the atom takes up most of its space?
    Neutron layer
    Proton field
    Nucleus
    Electron cloud
  • What type of radiation did Rutherford use?
    Electrons traveled in circles
    Alpha particles
    Gamma rays
    Beta particles
  • Which scientist first suggested atoms were the smallest unit of matter?
    Dalton
    Rutherford
    Millikan
    Thomson
  • Which observation from Rutherford supported the existence of a nucleus?
    Cathode rays glowed
    A few alpha particles rebounded
    Oil droplets floated
    Electrons traveled in circles
  • Which experiment first revealed that atoms contain empty space?
    Oil drop
    Gold foil
    Cathode ray tube
    Flame test
  • Millikan’s data showed that the electron’s charge was always a multiple of one small value. This proved that charge is:
    Random
    Constant and quantized
    Changing with temperature
    Increasing
  • The fact that a few alpha particles bounced back suggested the nucleus was:
    Negatively charged
    Spread out
    Dense and positive
    Very large
  • In modern terms, which part of Dalton’s theory is still correct?
    Atoms cannot be divided
    Atoms are identical
    Atoms make up all matter
    Atoms have no internal structure
  • Which sequence correctly shows how the understanding of atomic structure changed?
    Electron → Nucleus → Atom
    Nucleus → Solid sphere → Electron cloud
    Nucleus → Electron → Atom
    Solid sphere → Electron inside → Charged nucleus
  • According to Dalton, what combines in whole-number ratios to form compounds?
    Nuclei
    Elements
    Atoms
    Electrons
  • Millikan suspended oil droplets between charged plates. What force pulled the droplets downward?
    Gravity
    Light pressure
    Electromagnetic force
    Friction
  • Which scientist’s work allowed the calculation of the electron’s mass?
    Rutherford + Dalton
    Millikan alone
    Thomson alone
    Thomson + Millikan
  • What charge did Thomson conclude the particles in the cathode ray carried?
    Negative
    Neutral
    Positive
    Changing
  • Which idea from Dalton helped explain why chemical reactions always follow the same proportions?
    Atoms combine in fixed ratios
    Atoms have isotopes
    Atoms have a nucleus
    Atoms are indivisible
  • In Rutherford’s experiment, what would the plum-pudding model have predicted?
    All alpha particles bounce back
    Even scattering
    Almost no deflections
    Heavy deflections
  • Millikan adjusted the electric field until droplets stopped falling. What did this allow him to determine?
    The droplet’s volume
    The speed of the droplet
    The electron’s charge
    The nucleus’s size
  • Which scientist provided the first experimental evidence that atoms are not solid spheres?
    Dalton
    Rutherford
    Millikan
    Thomson
  • What caused the cathode ray to bend in Thomson’s experiment?
    A chemical reaction
    emperature changes
    Electric and magnetic fields
    Gravity
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