South Pasadena • Chemistry
Name
Period
Date
2 · Elements and Compounds
UNIT TEST



•
PRACTICE
You may use a pencil, eraser, and scientific calculator to complete the test. No other resources are allowed.
You have fifty (50) minutes to complete this test, unless other arrangements have been made.
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 12-16:
(A) Alkali Metal
(B) Alkaline Earth Metal
(C) Halogen
(D) Noble Gas
1. Does not carry a charge.
12. Gains one electron when forming an ion.
2. The atomic number of an element.
13. Includes Ca, Sr, and Ba
3. Has a mass of approximately 1/1800th amu
14. Are all diatomic elements.
4. Makes up the nucleus.
15. Are unreactive.
5. Is the same in 23Na+ and 23Mg2+
16. Has elements in solid, liquid, and gas forms at
standard state.
6. Determines the size of an atom.
Questions 7-11:
(A) Nitrogen, N
(B) Silicon, Si
(C) Krypton, Kr
(D) Strontium, Sr
7. A diatomic element.
8. Does not form ions.
9. An alkaline earth metal.
10. In the same period as Magnesium, Mg.
11. A semi-metal.
SECTION 2: MULTIPLE CHOICE. Select the best answer choice for each question. (2 points each)
17. Which statement best describes the atom?
(A) The protons and electrons determine the size
of the atom, while the neutrons make up most
of the mass.
(B) The protons and neutrons determine the size of
the atom, while the electrons make up most of
the mass.
(C) The protons and neutrons make up most of the
mass of the atom, while the electrons
determine the size.
(D) The protons, electrons, and neutrons
contribute equally to the mass and size of the
atom.
22. 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.
23. 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.
18. Which of the isotopes below has 7 neutrons?
(A) 7Li
(B) 13C
(C) 15N
(D) 19F
24. 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.
19. 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
25. The element bromine can be considered:
(A) a halogen
(B) a metalloid
(C) an alkali metal
(D) an alkaline earth metal
30
20. On the periodic table, the number
Zn
“65.38” on the element zinc
65.38
represents:
I. The number of protons and neutrons.
II. The average mass of all isotopes of zinc
atoms.
III. The total mass of 1 mole of zinc atoms.
(A) I only.
(B) II only.
(C) II and III only.
(D) I, II, and III.
26. Which of the following elements is NOT a solid at
standard state?
(A) Calcium, Ca
(B) Chlorine, Cl
(C) Cobalt, Co
(D) Copper, Cu
21. 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.
27. This element is in the same period as oxygen and
the same family as chlorine.
(A) Fluorine
(B) Nitrogen
(C) Silicon
(D) Sulfur
28. This diatomic element is in the same period as
potassium.
(A) Bromine
(B) Hydrogen
(C) Iodine
(D) Nitrogen
29. Organic compounds typically:
(A) Have only non-metal elements.
(B) Start with a metal.
(C) Start with carbon and hydrogen.
(D) Start with hydrogen.
31. Which of the following compounds is ionic?
(A) (CH3O)3P
(B) H3PO3
(C) K3PO4
(D) P4O10
30. 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.
32. 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.
33. Complete the following table. (6 points total)
Atomic
Number of
Isotope
Mass Number
Number
Protons
Number of
Neutrons
Number of
Electrons
22
18
60
46
Net Charge
31 3–
P
18
107
34. Consider hydrogen sulfide, H2S.
(a) What kind of compound is H2S (i.e. acid, covalent, ionic, or organic)? Briefly explain why. (2 pts)
(b) Find the molar mass of H2S. (4 pts)
(c) Find the percent composition of hydrogen in H2S. (4 pts)
(d) What is the volume of 0.65 moles of H2S at STP? (4 pts)
35. Consider the compound trinitrotoluene, C7H5(NO2)3. [This is TNT.]
(a) What is the molar mass of C7H5(NO2)3? (4 pts)
(b) What is the percent composition of nitrogen in C7H5(NO2)3? (4 pts)
(c) How many molecules are in 301.6 g of C7H5(NO2)3? (4 pts)
ANSWERS
1. B
2. C
3. A
9. D
10. B
11. B
17. C
18. B
19. D
25. A
26. B
27. A
33. (a) 15, 31, 15, 16, 18, –3;
34. (a) acid, starts with H;
35. (a) 227.14 g/mol
4. D
5. A
12. C
13. B
20. C
21. A
28. A
29. C
(b) 40Ar, 18, 40, 0;
(b) 34.07 g/mol
(b) 18.5%
6. A
7. A
8. C
14. C
15. D
16. C
22. C
23. D
24. B
30. C
31. C
32. C
(c) 107Ag+, 47, 47, +1
(c) 5.92%
(c) 7.99 × 1023 molecules
(d)14.56 L