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Unformatted text preview: Version 284 Exam 1 mccord (51600) 1 This printout should have 34 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. 001 10.0 points How many electrons can possess this set of quantum numbers: principal quantum num ber n = 4, angular quantum number = 2? 1. 14 2. 2 3. 18 4. 16 5. 6. 4 7. 12 8. 10 correct 9. 8 10. 6 Explanation: Use the rules for the quantum numbers: If n = 4 and = 2 ( i.e. , 4 d ), then m = 2 , 1 , , +1 , +2 are permitted; there are five different orbitals and m s = 1 2 , each holding two electrons. 002 10.0 points What is the maximum value that m can have for a 3 d orbital? 1. 1 2. 3 3. 2 4. 3 5. 6. 2 correct Explanation: m = , ..., , ..., For a d orbital = 2 . 003 10.0 points A given atomic orbital has a total of two nodal planes. What type of orbital is this? 1. d correct 2. g 3. s 4. p 5. f Explanation: A node is a point, a plane or a three dimen sional region of space where the sign of the wavefunction changes from positive to neg ative (or negative to positive), so it equals zero. The lowest energy orbital of each type will have no three dimensional nodes but dif fering numbers of nodal planes: 1 s no nodal planes 2 p one nodal plane (two opposing lobes of different signs) 3 d two nodal planes (four opposing lobes of two different signs) 4 f three nodal planes (six opposing lobes of two different signs) (One orbital has only one nodal plane and one conical node for both 3 d and 4 f .) If we go to the next higher value of n for the same type of orbital we would add a spherical (radial) node but the number of nodal planes would remain the same. 004 10.0 points How many electrons can possess this set of quantum numbers: principal quantum number n = 4, magnetic quantum number m = 1? Version 284 Exam 1 mccord (51600) 2 1. 2 2. 10 3. 18 4. 5. 16 6. 8 7. 6 correct 8. 12 9. 4 10. 14 Explanation: Use the rules for the quantum numbers: If n = 4 then = 0 , 1 , 2 , 3; however, for m = 1, = 1 , 2 , 3. Each of these permit ted sets of values of n , and m specifies ONE orbital: n = 4, = 1, m = 1: 4 p n = 4, = 2, m = 1: 4 d n = 4, = 3, m = 1: 4 f and each orbital can have m s = 1 2 ; i.e. , can hold two electrons. 005 10.0 points How many V( r ) terms are found in the solution to the Schr odinger equation for a Li + ion? 1. 1 V( r ) terms 2. 4 V( r ) terms 3. 3 V( r ) terms correct 4. 5 V( r ) terms 5. 2 V( r ) terms 6. 6 V( r ) terms Explanation: Each of the two electrons has an attrac tive potential energy term with the nucleus. And they mutually repel each other in a final potential energy term. 006 10.0 points In a onedimensional particle in a box, for n = 6, how many wavelengths equals the size of the box?...
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 Spring '11
 Dr.McCord

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