Name:______Date:______Period:____
Review Pre-AP Chemistry Unit 2: Atomic Theory and Structure
Define each of the following terms:
1. atom:
2. proton:
3. electron:
4. neutron:
5. nucleus:
6. 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. Atoms are tiny indivisible particles.
B. Atoms of the same element are identical.
C. Atoms of different elements can sometimes be identical.
D. 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. Electrons are negatively charged and are the lightest subatomic particle.
B. Protons are positively charged and have nearly the same mass as neutrons.
C. Neutrons have no charge and have no mass.
D. 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: Charge (+ , – , or 0 ) Mass (1 or 0)
Proton ______
Neutron ______
Electron ______
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?
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17. Based on Rutherford’s discovery of the nucleus, which model of the atom is thought to be true?
A. Protons, electrons, and neutrons are evenly distributed throughout the atom.
B. The nucleus is made of protons, electrons, and neutrons.
C. Electrons are located around the nucleus and occupy most of the volume.
D. The nucleus is made of electrons and protons.
18. All atoms of the same element have the same ____.
A. number of neutrons
B. number of protons
C. mass numbers
D. mass
19. What are atoms of the same element with different numbers of neutrons?
A. ions
B. atoms
C. numbers of electrons
D. isotopes
20. Explain why isotopes of the same element are not considered different elements.
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3575X
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. 35 protons, 35 neutrons, and 70 electrons
B. 35 protons, 75 neutrons, and 35 electrons
C. 75 protons, 35 neutrons, and 40 electrons
D. 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. Which of the following statements about atoms is FALSE?
A. Atoms of the same element can have different masses.
B. Isotopes of an element have different numbers of protons.
C. The nucleus of an atom has a positive charge.
D. Atoms are mostly empty space.
24. Which of the following statements about atoms and subatomic particles is FALSE?
A. Protons have a positive charge.
B. Electrons are negatively charged and have a mass of 1.
C. The nucleus of an atom is positively charged.
D. Neutrons are located in the nucleus of an atom.
25. 15 moles of sodium and 15 moles of carbon have the same number of ______.
A. atoms
B. grams
C. A and B
D. NONE of the above
Calculations and Mole Conversions
SHOW ALL WORK BOX your answer
molar mass
26. What is the molar mass of CaF2?
27. What is the molar mass of Fe3(PO4)2?
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particle ↔ mole
28. Convert 4.50 moles of Fe to atoms of Fe.
29. Convert 4.03 x 1022 molecules of water to moles of water.
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gram ↔ mole
30. Convert 0.300 moles of S to grams of S.
31. Convert 652 g Sn(CO3)2 to moles of Sn(CO3)2 . (MM = 238.73 g/mol)
particle ↔ gram
32. What is the mass in grams of 3.42 x 1024 atoms of C?
33. How many atoms of aluminum are in a 5.60 g sheet of aluminum foil?
34. How many molecules are in 237 g H2O (one cup of water)? (MM = 18.02 g/mol)
Mix of all 6 Mole Conversion Types
35. How many atoms are in 1.85 mol Pb?
36. How many molecules are in 120 g H2O2? (MM = 34.02 g/mol)
37. How many moles is 2.12 x 1024 molecules of PABA (sun block ingredient)?
38. What is the mass in grams of 4.78 x 1022 molecules of capsaicin, C18H27NO3?
(MM = 305.41 g/mol) (capsaicin makes chili peppers hot!!)
[Extra] What mass of gold would have the same number of atoms as 1000. g lead?
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