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Review Chemistry I Honors
Unit 3: Atomic Theory and Structure
Define each of the following terms:
1. atom:
2. proton:
3. electron:
4. neutron:
5. nucleus:
6. average atomic mass:
7. isotope:
8. mass number:
9. atomic number:
10. Avogadro’s number:
11. molar mass:
Circle or write in the correct answer:
12. Which of the following was originally a part of Dalton's atomic theory, but had to be revised later
based on new experimental evidence? (circle all that apply)
A.
B.
C.
D.
Atoms are tiny indivisible particles.
Atoms of the same element are identical.
Atoms of different elements can sometimes be identical.
Compounds are made by combining atoms.
13. Consider J.J. Thomson’s cathode ray tube experiment. Briefly describe what occurred that gave
evidence of electrons in all atoms.
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14. Which of the following is FALSE about subatomic particles?
A.
B.
C.
D.
Electrons are negatively charged and are the lightest subatomic particle.
Protons are positively charged and have nearly the same mass as neutrons.
Neutrons have no charge and have no mass.
The mass of a neutron nearly equals the mass of a proton.
15. All atoms are neutral because the number of __________________ always equals
the number of __________________ in every atom.
Fill in the chart with a charge and mass:
Proton
Neutron
Electron
Charge (+ , – , or 0 ) Mass (1 or 0)
____
____
____
____
____
____
Rutherford Gold Foil Experiment
gold
atom
expected results
gold
atom
actual results
16. What observations in this experiment by led to the theory that atoms are mostly empty space,
and that almost all of the mass of the atom is contained in a tiny, dense nucleus?
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
17. Based on Rutherford’s discovery of the nucleus, which model of the atom is thought to be true?
A.
B.
C.
D.
Protons, electrons, and neutrons are evenly distributed throughout the atom.
The nucleus is made of protons, electrons, and neutrons.
Electrons are located around the nucleus and occupy most of the volume.
The nucleus is made of electrons and protons.
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18. All atoms of the same element have the same ____.
A.
B.
C.
D.
number of neutrons
number of protons
mass numbers
mass
19. What are atoms of the same element with different numbers of neutrons?
A.
B.
C.
D.
ions
atoms
numbers of electrons
isotopes
20. Explain why isotopes of the same element are not considered different elements.
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___________________________________________________________________
75
35X
21. Element X has an atomic number of 35 and a mass number of 75.
How many of each subatomic particle are in a neutral atom of the element?
A.
B.
C.
D.
35 protons, 35 neutrons, and 70 electrons
35 protons, 75 neutrons, and 35 electrons
75 protons, 35 neutrons, and 40 electrons
35 protons, 40 neutrons, and 35 electrons
22. In which of the following is the number of neutrons correctly represented?
A.
F has 9 neutrons.
B.
As has 108 neutrons.
C.
Mg has 12 neutrons.
D.
U has 238 neutrons.
23. The weighted average atomic mass of the element chlorine is 35.45 amu, but the mass number of
a chlorine-37 atom is 37.
So how is the average atomic mass of an element different from the mass number of an atom?
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___________________________________________________________________
24. Which of the following statements about atoms is FALSE?
A.
B.
C.
D.
Atoms of the same element can have different masses.
Isotopes of an element have different numbers of protons.
The nucleus of an atom has a positive charge.
Atoms are mostly empty space.
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25. Which of the following statements about atoms and subatomic particles is FALSE?
A.
B.
C.
D.
Protons have a positive charge.
Electrons are negatively charged and have a mass of 1.
The nucleus of an atom is positively charged.
Neutrons are located in the nucleus of an atom.
26. 15 moles of sodium and 15 moles of carbon have the same number of _________.
A.
B.
C.
D.
atoms
grams
molecules
ALL of the above
27. The element silver has two naturally occurring isotopes:
silver-107 has an isotopic mass of 106.905 amu and a relative abundance of 51.84%
silver-109 has an isotopic mass of 108.905 amu and a relative abundance of 48.16%
Calculate the average atomic mass of the element silver. (SHOW ALL WORK)
28. The fictitious element Z has two naturally occurring isotopes, Z-310 and Z-313.
The average atomic mass of Z is found to be 311.02 amu. Which of the two isotopes of the
fictitious element Z is more abundant?
Z-310 or Z-313 or equal abundance (circle one)
How could you tell? _____________________________________________________________
Calculations and Mole Conversions
SHOW ALL WORK
BOX your answer
particle ↔ mole
29. Convert 4.50 moles of Fe to atoms of Fe.
30. Convert 4.03 x 1022 atoms of silver to moles of silver.
gram ↔ mole
31.
Convert 0.300 moles of S to grams of S.
32.
Convert 652 g lithium to moles of lithium.
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[KEY] REVIEW Unit 3: Atomic Theory and Structure
12. A, B
13. Every element released negatively charge cathode rays that bent toward a positive plate.
14. C
15. protons, electrons
proton +1 1
neutron 0 1
electron –1 0
16. Most of the alpha particles traveled through the gold atoms showing atoms are mostly empty space.
Very few positively charged alpha particles deflected revealing a tiny, dense, positive region in atoms.
17. C
18. B
19. D
20. They are isotopes b/c they have different numbers of neutrons, but they are the same element b/c they
have the same number of protons (same atomic number).
21. D
22. C
23. Average atomic mass is a “weighted” average of all atoms of an element that depends on the relative
abundance (amount) of each isotope of an element, but mass number is just the number of protons and
neutrons in one single atom of an element.
24. B
25. B
26. A
27. (106.905 amu)(0.5184) + (108.905 amu)(0.4816) = 107.868 amu
28. Z-310 b/c the weighted average atomic mass (311.02 amu) is closest to the isotopic mass of Z-310.
29. 2.71 x 1024 atoms
30. 0.0669 mol
31. 9.62 g
32. 2.73 mol
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