# Exam 1 - Version 725 Exam 1 Mccord(50970 This print-out...

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Version 725 – Exam 1 – Mccord – (50970) 1 This print-out should have 31 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points The higher the energy of electromagnetic ra- diation, the 1. longer its wavelength. 2. greater its mass. 3. higher the velocity of light. 4. lower its frequency. 5. shorter its wavelength. correct 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). Thus, the equation that relates energy to wavelength for electromagnetic radiation is E = h c λ As energy increases, ν (frequency) must also increase, and λ (wavelength) must decrease. 002 10.0 points Which of the following best describes the range of atomic radii? 2. 1 to 15 ˚ A 3. 5 to 10 ˚ A 4. 10 to 30 ˚ A 5. 0.4 to 3 ˚ A correct 6. 1 to 100 ˚ A Explanation: Atomic radii vary from 30 pm (He) to 300 pm (Fr). 1 ˚ A= 10 - 10 m = 100 pm, so the range of atomic radii is 0.3 to 3 ˚ A. 003 10.0 points In a many-electron atom, any two electrons 1. have a different energy. 2. can have either the same or a different energy. correct 3. have the same energy. Explanation: Energy is determined by distance. Elec- trons can have the same energy (distance from the nucleus) but have different sets of quan- tum numbers. 004 10.0 points Write the ground-state electron configuration of a lead atom. 1. [Xe] 4 f 14 5 d 10 6 s 1 6 p 3 2. [Xe] 4 f 14 5 d 9 6 s 2 6 p 3 3. [Xe] 4 f 14 5 d 10 6 s 2 6 p 2 correct 4. [Xe] 4 f 14 5 d 10 6 p 4 5. [Xe] 4 f 14 5 d 5 6 s 1 6 p 6 7 s 2 [Xe] 4 f 14 5 d 10 6 s 2 6 p 2 .
Version 725 – Exam 1 – Mccord – (50970) 2 005 10.0 points What is the de Broglie wavelength of a bowl- ing ball rolling down a bowling alley lane? Assume the mass of the ball is 4500 g and it is moving at 4.12 m/s. 1. 3 . 574 × 10 - 38 m 2. 3 . 57389 × 10 - 35 m correct 3. 1 . 4725 × 10 - 37 m 4. 1 . 229 × 10 - 32 m 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. Explanation:
006 10.0 points How many electrons can possess this set of quantum numbers: principal quantum number n = 4, magnetic quantum number m = - 1?
9. 16 10. 12