Unit 5 - Mark Rosengarten

2) One model of the atom states that atoms are tiny particles composed of a uniform mixture of positive and
negative charges. Scientists conducted an experiment where alpha particles were aimed at a thin layer of
gold atoms. Most of the alpha particles passed directly through the gold atoms. A few alpha particles were
deflected from their straight-line paths. (This question was taken directly from a Regents Exam).
a) Most of the alpha particles passed directly through the gold atoms undisturbed. What does this evidence
suggest about the structure of gold atoms?
b) A few of the alpha particles were deflected from their straight path as they passed through the gold foil. What
does this evidence suggest about the structure of the gold atoms?
c) How should the original model (the one that says that atoms are tiny particles composed of a uniform mixture
of positive and negative charges) be revised based on the results of this experiment? This question is not
asking how the EXPERIMENT should have been changed, but how the MODEL (the idea of what the atom
looks like) should be changed.
3) Internet Research!!!! About forty years ago, it was discovered that protons and neutrons are made up of
smaller particles called quarks. There are six types (flavors) of quarks.
a) What are the six flavors of quarks called?
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b) What flavors and how many of each go into making a proton?
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c) What flavors and how many of each go into making a neutron?
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d) List the URL’s (web addresses) of the sites you got this information from:
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© 2011, Mark Rosengarten R 22