solutions - Version 119 Exam 1 McCord (91750) 1 This...

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Unformatted text preview: Version 119 Exam 1 McCord (91750) 1 This print-out should have 30 questions. Multiple-choice 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 one-dimensional 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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solutions - Version 119 Exam 1 McCord (91750) 1 This...

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