Cliffs AP Chemistry, 3rd Edition

Samples: Free-Response Questions

1. The electon configuration of an element determines its chemical properties. For the
   elements sodium, magnesium, sulfur, chlorine, and argon, provide evidence that
   illustrates this statement and show how the evidence supports the statement.

Answer

1. Restatement: Electron configuration and chemical properties for Na, Mg, S, Cl, and Ar.
   This question lends itself to the outline format.
   I. Sodium, Na
   A. Electron configuration ls^22 s^22 p^6 3s^1

B. Lewis diagram Na ⋅

C. Alkali metal

D. Chemical properties

1. Loses valence electron easily


2. Very reactive


3. Low ionization energy


4. Reacts with nonmetals to form ionic solid


5. When reacting with nonmetal, metal acts as a reducing agent
   II.Magnesium, Mg
   A. Electron configuration 1s^22 s^22 p^63 s^2
   B. Lewis diagram Mg :
   C. Alkaline earth metal
   D. Chemical properties


6. Forms only divalent compounds that are stable and have high heats of formation


7. Very reactive only at high temperatures


8. Powerful reducing agent when heated


9. Reacts with most acids


10. Burns rapidly in air (O 2 )
    III. Sulfur, S
    A. Electron configuration ls^22 s^22 p^63 s^23 p^4
    B. Lewis diagram

S

Electronic Structure of Atoms