South Pasadena • Honors Chemistry
Name
2 · Elements and Compounds
Period
UNIT TEST
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Date
•
PRACTICE
You may use a pencil, eraser, and scientific calculator to complete the test. No other resources are allowed.
Please transfer your answers for Matching and Multiple Choice questions onto the Answer Document. Work
for the Matching and Multiple Choice questions will not be graded. However, sufficient and appropriate
work must be shown for the Free Response questions in order to receive full credit.
SECTION 1: MATCHING. Use the following answer choices that best match each description. Answer
choices may be used once, more than once, or not at all. (1 point each)
Questions 1-6:
(A) Electron only.
(B) Neutron only.
(C) Proton only.
(D) Proton and neutron only.
Questions 11-14:
(A) Alkali Metal
(B) Alkaline Earth Metal
(C) Halogen
(D) Noble Gas
1. Does not carry a charge.
11. Gains one electron when forming an ion.
2. The atomic number of an element.
12. Are all diatomic elements.
3. Has a mass of approximately 1/1800th amu
13. Are unreactive.
4. Makes up the nucleus.
14. Has elements in solid, liquid, and gas forms at
standard state.
5. Is the same in 23Na+ and 23Mg2+
6. Determines the size of an atom.
Questions 7-10:
(A) Nitrogen, N
(B) Silicon, Si
(C) Krypton, Kr
(D) Strontium, Sr
7. Does not form ions.
8. An alkaline earth metal.
9. In the same period as Magnesium, Mg.
10. A semi-metal.
SECTION 2: TRUE/FALSE. (1 point each)
Evaluate the statement in column 1. If it’s TRUE, fill in bubble A. If it’s FALSE, fill in bubble B.
Evaluate the statement in column 2. If it’s TRUE, fill in bubble C. If it’s FALSE, fill in bubble D.
If column 2 is the correct explanation for column 1, then bubble E.
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If both columns are TRUE, but column 2 is the correct explanation, bubble ACE.
If both columns are TRUE, but column 2 is not the correct explanation, bubble AC.
If column 1 is TRUE and column 2 is FALSE, bubble AD.
If column 1 is FALSE and column 2 is TRUE, bubble BC.
If column 1 is FALSE and column 2 is FALSE, bubble BD.
15.
40
Column 1
Ca and Ca are isotopes of each other
42
BECAUSE
Column 2
they have the same number of protons.
16. Chlorine and iodine have similar chemical
properties
BECAUSE
they are in the same family on the Periodic
Table.
17. NH4Cl and CH3Cl are examples of covalent
compounds
BECAUSE
they are composed of non-metal atoms.
SECTION 3: MULTIPLE CHOICE. Select the best answer choice for each question. (1 point each)
18. The cathode-ray tube experiments by J. J.
Thomson showed that:
(A) Atoms are indivisible.
(B) Electrons are a form of light.
(C) Most of the atom is empty space.
(D) Small, negatively-charged electrons exists.
19. An atom of zinc has a mass of 65.9260 amu.
Which if the following is true?
(A) It has 36 electrons.
(B) It has 36 neutrons.
(C) It has 66 neutrons.
(D) It has 66 protons.
20. Which of the isotopes below has 7 neutrons?
(A) 7Li
(B) 13C
(C) 15N
(D) 19F
21. Which of the following has a net charge of +2?
(A) Protons = 2, Neutrons = 2, Electrons = 2
(B) Protons = 4, Neutrons = 6, Electrons = 4
(C) Protons =16, Neutrons = 18, Electrons = 18
(D) Protons = 20, Neutrons = 40, Electrons = 18
20
22. On the periodic table, the number
“40.08” on the element calcium
Ca
40.08
represents:
I. The number of protons and neutrons.
II. The average mass of all isotopes of
calcium atoms.
III. The total mass of 1 mole of calcium
atoms.
(A) I only.
(B) II only.
(C) II and III only.
(D) I, II, and III.
23. The element rhenium, Re (atomic number 75),
exists in two isotopes: rhenium-185 and rhenium187. Which isotope is more abundant?
(A) Rhenium-185
(B) Rhenium-187
(C) They have equally abundant.
(D) It cannot be determined.
Questions 27-28: Refer to the following molecular
snapshot of a sample.
Question 24: Refer to the following plot.
27. The sample shown above is:
(A) A mixture of elements.
(B) A mixture of elements and compounds.
(C) A pure substance of elements.
(D) A pure substance of compounds.
24. A sample of an element X was run through a mass
spectrometer and the plot above was obtained.
What conclusion cannot be drawn about element
X from the plot?
(A) Element X exists in two isotopes.
(B) Element X forms a +2 ion.
(C) The molar mass of element X is between 121
and 123 g/mol.
(D) The X-121 isotope is more abundant than the
X-123 isotope.
25. The state of matter that is the least dense is:
(A) Solid
(B) Liquid
(C) Gas
(D) The states have the same density if it’s the
same substance.
26. Which of the following is a characteristic of nonmetals?
(A) They are ductile.
(B) They are insulators of heat.
(C) They are nearly all solids.
(D) They form positive ions.
28. The sample is probably in which state?
(A) Gas.
(B) Solid.
(C) Liquid.
(D) Liquid and gas.
29. Which of the following elements is NOT a solid at
standard state?
(A) Calcium
(B) Chlorine
(C) Cobalt
(D) Copper
30. This diatomic element is in the same family as
sodium.
(A) Chlorine
(B) Hydrogen
(C) Iodine
(D) Oxygen
31. Metal X combines with chlorine to form XCl2.
What compound does it form with sulfate?
(A) XSO4
(B) X2SO4
(C) X(SO4)2
(D) X2(SO4)2
32. Solids are different from liquids because solids
(A) Have fixed shape.
(B) Have fixed volume.
(C) Take on the shape of their container.
(D) Take on the volume of their container.
33. The element bromine can be considered:
(A) a halogen
(B) a metalloid
(C) an alkali metal
(D) an alkaline earth metal
34. A sample of solid P4 can be considered:
(A) Atoms of a compound.
(B) Atoms of an element.
(C) Molecules of a compound.
(D) Molecules of an element.
35. This element is in the same period as oxygen and
the same family as chlorine.
(A) Fluorine
(B) Nitrogen
(C) Silicon
(D) Sulfur
36. Organic compounds typically:
(A) Have only non-metal elements.
(B) Start with a metal.
(C) Start with carbon and hydrogen.
(D) Start with hydrogen.
37. Which of the following is the correct name for
AuCl3?
(A) Gold chloride
(B) Gold trichloride
(C) Gold(III) chloride
(D) Gold(III) trichloride
38. Which of the following compounds is ionic?
(A) (CH3O)3P
(B) H3PO3
(C) K3PO4
(D) P4O10
39. Hypochlorous acid refers to:
(A) HCl
(B) HClO
(C) HClO2
(D) HClO3
40. Which of the following is the correct balanced
equation for the decomposition of cupric oxide?
(A) 2 Cu2O (s)  4 Cu (s) + O2 (g)
(B) 2 CuO (s)  2 Cu (s) + O2 (g)
(C) CuO (s)  Cu (s) + O (g)
(D) CuO2 (s)  Cu (s) + O2 (g)
41. Which of the following compounds is formed
when stannic and oxide ions combine?
(A) Sn2O4
(B) Sn4O2
(C) SnO
(D) SnO2
42. Which of these correctly pairs the empirical and
molecular formulas of a compound?
(A) C3H6 … C3H8
(B) CH2 … C4H8
(C) NO2 … CS2
(D) P2I4 … N2O4
43. An oxide of manganese contains 30.4% oxygen by
mass. What is the chemical formula of the
compound?
(A) MnO
(B) MnO2
(C) Mn2O3
(D) Mn2O7
44. One mole of CO2 (gas) and one mole of CH4 (gas)
have which of the following in common?
I. They have the same mass.
II. They have the same number of molecules.
III. They occupy the same volume at STP.
(A) I only.
(B) II only.
(C) II and III only.
(D) I, II, and III.
45. Which of the following is NOT true about a onemole sample of NO2?
(A) It occupies 22.4 L at STP.
(B) It has a mass of 46.0 g.
(C) There are 6.02 × 1023 oxygen atoms.
(D) It has the same number of particles as 16.00 g
oxygen atoms.
SECTION 3: FREE RESPONSE. Show all your work to receive full credit.
46. Complete the following table. (6 points total)
Isotope
Atomic Number
Mass Number
Number of
Protons
Number of
Neutrons
Number of
Electrons
18
22
18
60
46
Net Charge
31 3–
P
107
47. For each compound, identify whether it’s an ionic compound, a covalent compound, or an acid. Then write
the name or formula of the compound. (6 points)
Name
(a)
(b)
Ferric carbonate
HBrO4
Iodine heptachloride
(e)
(f)
I/C/A
K3PO4
(c)
(d)
Formula
CrO3
Nitrous acid
48. Consider the compound trinitrotoluene, C7H5(NO2)3. [This is TNT.]
(a) What kind of compound is H2S (i.e. acid, covalent, ionic, or organic)? Briefly explain why. (2 pts)
(b) What is the molar mass of C7H5(NO2)3? (4 pts)
(c) What is the percent composition of nitrogen in C7H5(NO2)3? (4 pts)
(d) How many molecules are in 301.6 g of C7H5(NO2)3? (4 pts)
49. A sample of an oxide of iron (FexOy) was heated in a crucible. The following masses were recorded.
Mass of crucible:
28.7210 g
Initial mass of crucible and solid: 30.2040 g
Final mass of crucible and solid:
29.7585 g
Assume that oxygen was completely vaporized.
(a) Calculate the masses of iron and oxygen in the original sample. (4 pts)
(b) Find the empirical formula for the compound. (4 pts)
(c) If the molar mass of the compound is around 160 g/mol, find the molecular formula for the compound.
(4 pts)
(d) Write the balanced equation for the decomposition of the compound. (2 pts)
50. Gallium, Ga (atomic number 31), exists as Ga-69 and Ga-71, with masses 68.9256 amu and 70.9247 amu,
respectively.
(a) Find the abundance of each isotope. (4 pts)
(b) Sketch what the mass spectrometer plot might look like. Explain briefly the number and height of the
peaks. (4 pts)