Page 26 - Surviving Chemistry BFF Homework Helper and Test Prep Preview

8. J.J. Thomson:

A cathode ray tube containing two metal disks was
connected to the + and – ends of an electrical source.
A positive (+) and negative (-) plates were placed above

and below the cathode ray tube.

A beam of light (ray) travels from the cathode disk (-) to
Result 1 the anode disk (+).

The beam is composed of particles.
Conclusion 1

Result 2 The beam was deflected toward the positive plate.

Conclusion 2 The particles in the beam are negatively charged (electrons).

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9. Ernest
Rutherford:

were fired at a gold foil.
The Setup

A fluorescent screen detects paths of the alpha particles
once they had hit the gold foil.

Result 1 Most particles went straight through the gold foil
undeflected.

Conclusion 1 An atom is mostly empty space (Empty Space Theory)

Result 2 Very few particles were deflected straight back or at
angles.

Conclusion 2 The center of an atom is dense, positive, and very small.

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