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Unformatted text preview: Version 119 Exam 1 McCord (91750) 1 This printout should have 30 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. 001 7.0 points Which set of quantum numbers does NOT provide a satisfactory solution to the wave equation? 1. n = 4, = 3, m = 3 correct 2. n = 4, = 3, m = 0 3. n = 4, = 2, m = 1 4. n = 4, = 2, m = +2 5. n = 4, = 3, m = 1 Explanation: 002 7.0 points If a particle is confined to a onedimensional box of length 300 pm, for 3 the particle is most likely to be found at 1. 50, 150, and 250 pm, respectively. cor rect 2. 100 and 200 pm, respectively. 3. 300 pm. 4. 0 pm. 5. 17.3 pm. Explanation: 003 7.0 points Which set of quantum numbers, n , , m , could correspond to one of the highest energy electrons in Zr? 1. 3, 2, 2 2. 4, 2, 2 correct 3. 4, 2, +3 4. 4, 3, 2 Explanation: Zr has the electron configuration [Kr] 5 s 2 4 d 2 . The highest energy orbital is 5 s but this requires that n = 5, which is not a choice. The next highest energy level orb tials are the 4 d where n = 4, = 2 and m = 2 , 1 , , +1 , +2. 004 7.0 points How many unpaired electrons are there in the ground state electron configuration of an Fe atom? 1. 2. 1 3. 3 4. 2 5. 4 correct Explanation: 005 7.0 points The atomic weight of a newly discovered el ement is 110.352 amu. It has two naturally occuring isotopes. One has a mass of 111.624 amu. The other has an isotopic mass of 109.875 amu. What is the percent abundance of the last isotope (109.875 amu)? 1. 72.7% correct 2. 62.5% 3. 37.5% 4. 54.2% 5. 45.8% 6. 27.3% Explanation: Let x = the percent abundance of the last isotope. Then the percent abundance of the first isotope would be 1 x . Remember that Version 119 Exam 1 McCord (91750) 2 x is the decimal form of the percent, and is some fraction of 1. (109 . 875) x + (111 . 624)(1 x ) = 110 . 352 109 . 875 x + 111 . 624 111 . 624 x = 110 . 352 1 . 749 x = 1 . 272 x = 0 . 727 = 72 . 7% 006 7.0 points One of the following does NOT represent the ground state electron configuration for an atom. Which one? 1. [Ne] 3 s 2 3 p 6 2. [Ne] 3 s 1 3. [Ne] 3 s 1 3 p 3 correct 4. [Ne] 3 s 2 5. [Ne] 3 s 2 3 p 5 Explanation: 007 7.0 points The coinage metals, Cu, Ag, and Au, all lie in one column of the periodic table. Consider Ag. An atom of Ag will have a certain ground state electron configuration according to the Aufbau principle. The outermost electrons in Ag will have the configuration 1. 5 s 2 5 p 6 4 d 9 . 2. 5 s 2 5 p 6 4 d 3 . 3. 5 s 2 4 d 9 . 4. 5 s 1 4 d 10 . correct 5. 5 s 1 5 p 6 4 d 4 . Explanation: These metals are an exception to the gen eral trend of filing. Note the column is some times labelled IB....
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This note was uploaded on 08/29/2008 for the course CH 301 taught by Professor Fakhreddine/lyon during the Summer '07 term at University of Texas.
 Summer '07
 Fakhreddine/Lyon

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