Download Unit 10 Test Review

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Chemistry – Unit 10 Test review
1.
Which atomic particles are equal in mass?
2. What are the number of protons in an atom called?
3. Experiments with the cathode-ray tube demonstrated that
4. J.J. Thomson
a. discovered the nucleus of the atom
b. concluded that the particles in the cathode beam had a (–) charge
c. discovered the neutron
d. based his experiments on results obtained by Rutherford
5. The part of Thomson’s model that was not supported by direct evidence was that
a. the atom was a sphere of uniform positive charge.
b. the positive charge of an atom was concentrated in a tiny nucleus.
c. electrons circled the nucleus like planets around the sun.
d. the atomic number equaled the number of protons in the nucleus.
6. The charge of the radioactive particle used in the gold foil experiments was
7. Rutherford’s gold foil experiment indicated that
a. the nucleus of an atom occupies most an atom’s volume
b. positive charges are dispersed throughout the atom
c. positive charges are concentrated in a very small core at the atom’s center
d. protons and neutrons are located in the nucleus
8. What are cathode rays?
9. With the discovery of isotopes, which part of Dalton’s original atomic theory
must be modified?
10. The lines in the bright line spectrum of an element are due to
a. movement of electrons in circular orbits.
b. movement of electrons from higher energy states to lower energy states.
c. movement of electrons from lower energy states to higher energy states.
d. movement of electrons as they fall into the nucleus.
11. How many neutrons are contained in an atom of strontium-88?
12. Which of the following represents a pair of isotopes?
a. H2O, H2O2
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b. 11H, 12H
c. 126 C, 147 N
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d. O2, O3
Unit 10 test review
13. In Rutherford’s gold foil experiment most of the alpha particles passed straight
through the foil, but some were deflected at wide angles. Briefly state in complete
sentences how these experimental observations could not have been explained by
Thomson’s model of the atom. A sketch of a Thomson atom will aid your
explanation.
14. Pictured below is the mass spectrogram of a transition metal.
a. What are the molar masses of the isotopes?
b. Based on the experimentally obtained values of molar mass and percent
abundance, calculate the average molar mass of the element. Show your work
below.
c. What are the symbols, including superscripts and subscripts, of the isotopes of
this element?
15. The figure at right shows a spectrograph of isotopes of the element germanium.
Match the letters of the lines in the spectrum with the correct description below.
least abundant
least massive
16. The relative abundances of isotopes of Element X in nature are
molar mass = 28, 92.21%,
molar mass = 29,
4.70%,
molar mass = 30,
3.09%.
Calculate the average molar mass of Element X and identify the element.
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Unit 10 test review