5 Steps to a 5 AP Chemistry

1. C—All the other elements are nonmetals.
   Nonmetals usually form monatomic anions.


2. A—The element can not be a metal (Na) or
   a noble gas (He). A nonmetal that can have
   a +6 oxidation state is needed. P has a maximum
   of +5. Cl may be +5 or +7. Se, in column 6A,
   can easily be +6.


3. A—Based on their positions on the periodic
   table:

C +4 to –4

F –1 and 0 (element)

O –2 to 0

Ca +2 and 0

Na +1 and 0

4. E—Isotopes MUST have the same number of
   protons. Different isotopes have different
   numbers of neutrons.


5. A—All the others are in decreasing order.


6. B—In general, the element furthest from F on
   the periodic table will have the lowest
   electronegativity. There are exceptions.


7. E—The very large iodine atom gains an electron
   to make it even larger.


8. D—The definition of electron affinity is: the
   energy change when a ground-state gaseous
   atom adds an electron.


9. D—The more electrons removed, the higher the
   values should be. The large increase between the
   first and second ionization energies indicates a
   change in electron shell. The element, X, has
   only 1 valence electron. This is true for Na. For
   the other elements the numbers of valence
   electrons are: Mg—2; Cl—7; Al—3; and Si—4.


10. E—The increase in the number of protons in
    the nucleus has a greater attraction for the elec-
    trons being added in the same energy level.
    Thus, the electrons are pulled closer to the
    nucleus and the size slightly decreases.
    11. A—The only other gas is radon, and it is inert.
    12. B—Sodium and radium are metals on the left
    side of the periodic table. Metals on the left side
    of the periodic table are very reactive.
    13. B—Ferrate(III) means Fe^3 +, while trisoxalato
    means (C 2 O 4 ) 36 −; three potassiums are needed to
    balance the charge.
    14. A—B is blue; C is orange; D is pink to red; and
    E is green.
    15. A—Chlorine is a gas; all the others are solids.
    16. D—Magnesium is present in chlorophyll.
    17. E—Aluminum forms a protective oxide
    coating.
    18. B—Gallium is one of the elements that will
    improve the conductivity of germanium.
    19. A—B is purple; C is green; D is colorless; and
    E is pink to red.
    20. A—Fractional crystallization works because the
    less soluble material separates first.
    21. C—A could be Li or Sr; B is Ca; D is K; and
    E is Na.
    22. C—A weak base with water to disperse the heat
    is the best choice.
    23. B—A solution containing a colored substance is
    needed.
    24. A—Separation of materials in solution is
    normally not simple. Reverseosmosis would also
    work.
    25. A—Rutherford proved the existence of the
    nucleus.

Basics  63

 Answers and Explanations

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