Cracking the SAT Chemistry Subject Test

CHAPTER 6 ELECTRON CONFIGURATIONS

AND RADIOACTIVITY

Drill 1

1. B You may be tempted to pick (E), but don’t. Atomic theory is
   associated with a fellow named Dalton and says that all elements are
   composed of atoms. For this test, you’re not expected to fully understand
   the De Broglie hypothesis; you’re just supposed to associate it with the idea
   that matter can be conceived of as waves, and waves can be conceived of as
   matter. So (B) is correct.


2. A You learned that Bohr incorrectly believed that electrons circled the
   nucleus in orbits, the way planets circle the sun. So (A) is correct.


3. C For this test, you need not completely understand the Heisenberg
   principle; you only need to associate it with the idea that one cannot, at any
   one moment, know both an electron’s position and momentum. So (C) is
   correct.


4. T, T Divide and conquer! Evaluate the first statement on its own, and
   decide whether it’s true or false. Is it true that according to the Bohr
   model electrons circle the nucleus in true orbits? Yes, it is.
   Now, look at the second statement by itself. Is it true?
   Yes. Now let’s find out if the sentence makes sense.
   “The Bohr model of the atom is inaccurate because an
   element may exist as several isotopes each with a
   different number of neutrons in the nucleus.” The
   second part of the statement has nothing to do with the
   first. Both statements are true, but they have nothing to
   do with each other, so do not fill in the CE oval.


5. F, T Evaluate the first statement by itself, and decide whether it’s true or
   false. Is it true that krypton is an unstable atom? No, that isn’t true.
   Krypton is a very stable atom. Why? Because it has a full octet in its