Transcript SC-100 Unit 8 Homework Assignment

SC-100
Class 13 Review Questions
• 1. One difference between the motion of electrons
in an atom and the motion of planets in the solar
systems is that
– a. gravity holds the planets in orbit while centripetal
force holds the electrons.
– b. planetary orbits are quantized, electron orbits are not.
– c. Brownian motion applies to planets but not electrons.
– d. planets can change their orbits and electrons
cannot.
– e. All of the above apply to both planets and electrons.
SC-100
Class 13 Review Questions
• 2. Materials made from a single type of
atom that cannot be broken down any
further are called
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a. atoms.
b. elements.
c. molecules.
d. solutions.
e. compounds.
SC-100
Class 13 Review Questions
• 3. The fundamental building block for all
matter; the smallest representative sample
of a substance that maintains chemical
identity.
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a. atom
b. element
c. molecule
d. electron
e. compound
SC-100
Class 13 Review Questions
• 4. We know that atoms have a nucleus because
– a. alpha particles exist.
– b. this is a necessary philosophical consequence of the
requirement that there be change in the world.
– c. the Rutherford experiment on the scattering of
alpha particles from gold gives evidence for it.
– d. there are no isolated monopoles in nature.
– e. None of the above are evidence for the existence of
the nucleus.
SC-100
Class 13 Review Questions
• 5. Electrons in the Bohr atom shift to a
higher energy level by
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a. absorbing the energy of light or heat.
b. reflecting the energy of heat or light.
c. emitting a photon.
d. producing an individual electromagnetic
wave.
– e. Electrons in the Bohr atom cannot change
energy states.
SC-100
Class 13 Review Questions
• 6. Each electron shell corresponds to a
different
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a. electron.
b. element.
c. ion.
d. atom.
e. energy level.
SC-100
Class 13 Review Questions
• 7. If an electron moves from a higher
energy shell to a lower energy shell
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a. a photon is emitted.
b. a photon is absorbed.
c. an observer will see light.
d. the electron disappears between shells.
e. a & c & d
SC-100
Class 13 Review Questions
• 8. In the periodic table of the elements, the
atomic number equals
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a. the number of protons in the nucleus.
b. the number of neutrons in the nucleus.
c. the number of electrons in the outer shell.
d. the mass of the atom.
e. the mass of the photon.