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Unformatted text preview: Version 912 – Exam 1 – Mccord – (50970) 1 This printout should have 31 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 10.0 points How many electrons could be described by the quantum numbers n = 5 and m s = + 1 2 ? 1. 1 2. 2 3. 5 4. 25 correct 5. 50 Explanation: For a given principle energy level, n , a total of 2 n 2 electrons are described. Exactly half of those, n 2 , will have a + 1 2 spin. 002 10.0 points An electron is confined to a onedimensional box of length L. It falls from the second en ergy level to the ground state, and releases a photon with a wavelength of 322 nm. What is the length of the box? 1. 292 nm. 2. 322 nm. 3. 0.541 nm. correct 4. 4.32 nm. 5. 0.151 nm. 6. 1.61 nm. 7. 0.303 nm. 8. 1.14 nm. 9. 2.92 nm. Explanation: 003 10.0 points What is the maximum number of electrons that will fill one 6 p orbital? 1. 6 2. 2 correct 3. 3 4. 10 5. 5 Explanation: No matter the orbital, the maximum num ber of electrons is 2. Those 2 electrons MUST have opposite spins. 004 10.0 points How many s electrons and p electrons does Mn possess? 1. 7 s , 12 p 2. 8 s , 6 p 3. 7 s , 13 p 4. 6 s , 18 p 5. 8 s , 12 p correct 6. 6 s , 6 p 7. 7 s , 18 p 8. 8 s , 18 p 9. 6 s , 12 p Explanation: The electron configuration for Mn is 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 4 s 2 3 d 5 2 + 2 + 2 + 2 = 8 s 6 + 6 = 12 p 005 10.0 points How many electrons can possess this set of Version 912 – Exam 1 – Mccord – (50970) 2 quantum numbers: principal quantum num ber n = 4, angular quantum number ℓ = 2? 1. 10 correct 2. 12 3. 4. 14 5. 6 6. 8 7. 4 8. 2 9. 18 10. 16 Explanation: Use the rules for the quantum numbers: If n = 4 and ℓ = 2 ( i.e. , 4 d ), then m ℓ = 2 , 1 , , +1 , +2 are permitted; there are five different orbitals and m s = ± 1 2 , each holding two electrons. 006 10.0 points How many electrons can possess this set of quantum numbers: principal quantum number n = 4, magnetic quantum number m ℓ = 1? 1. 4 2. 8 3. 12 4. 2 5. 6. 18 7. 10 8. 6 correct 9. 16 10. 14 Explanation: Use the rules for the quantum numbers: If n = 4 then ℓ = 0 , 1 , 2 , 3; however, for m ℓ = 1, ℓ = 1 , 2 , 3. Each of these permit ted sets of values of n , ℓ and m ℓ specifies ONE orbital: n = 4, ℓ = 1, m ℓ = 1: 4 p n = 4, ℓ = 2, m ℓ = 1: 4 d n = 4, ℓ = 3, m ℓ = 1: 4 f and each orbital can have m s = ± 1 2 ; i.e. , can hold two electrons. 007 10.0 points The higher the energy of electromagnetic ra diation, the 1. shorter its wavelength. correct 2. lower its frequency. 3. longer its wavelength. 4. greater its mass. 5. higher the velocity of light. Explanation: For electromagnetic radiation, the energy of radiation is related to its frequency by the equation E = h ν , where h is Planck’s constant, ν = c λ , and c is the speed of light in a vacuum (also a constant)....
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This note was uploaded on 11/07/2010 for the course CH 301 taught by Professor Fakhreddine/lyon during the Fall '07 term at University of Texas.
 Fall '07
 Fakhreddine/Lyon
 Chemistry, Electron

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