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Unformatted text preview: Version 777 – 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 shape of an atomic orbital is determined by which quantum number? 1. n 2. m ℓ 3. m s 4. ℓ correct Explanation: ℓ is the angular momentum quantum num- ber. It determines the shape of an atomic orbital. 002 10.0 points Write an equation for the second ionization energy of calcium. 1. Ca + (g) + e- → Ca- (g) 2. Ca + (g) + e- → Ca(g) 3. Ca + (g) → Ca 2+ (g) + e- correct 4. Ca + (g) + 2 e- → Ca 2+ (g) 5. Ca(g) → Ca 2+ (g) + 2 e- Explanation: Definition 003 0.0 points EXTRA CREDIT If more points are awarded on this assign- ment, would you like them added to your score? 1. NO, leave my score alone, I prefer the lower score 2. YES, I would like the points and the higher score. correct Explanation: This should be a no-brainer. Most students want higher scores. If you picked yes, you got credit for the question and you got the extra points you asked for (if they were granted by your instructor). If you answered NO, you also got what you wanted... no points awarded. 004 10.0 points If a particle is confined to a one-dimensional box of length 300 pm, for Ψ 3 the particle is most likely to be found at 1. 0 pm. 2. 100 and 200 pm, respectively. 3. 300 pm. 4. 17.3 pm. 5. 50, 150, and 250 pm, respectively. cor- rect Explanation: 005 10.0 points An electron in a 3 d orbital could have which of the following quantum numbers? 1. n = 2; ℓ = 3; m ℓ = 0 2. n = 3; ℓ = 0; m ℓ = 0 3. n = 3; ℓ = 3; m ℓ = 1 4. n = 3; ℓ = 2; m ℓ =- 3 5. n = 3; ℓ = 2; m ℓ = 0 correct 6. n = 2; ℓ = 2; m ℓ = 2 7. n = 3; ℓ = 1; m ℓ =- 1 Explanation: 3 refers to the principal quantum number n . d corresponds to the subsidiary quantum number ℓ = 2. Since ℓ = 2, m ℓ could be- 2 ,- 1 , , 1 or 2. Version 777 – Exam 1 – Mccord – (50970) 2 006 10.0 points Note: “same intensity” means the same num- ber of photons per second. We conduct an experiment by shining 500 nm light on potassium metal. This causes electrons to be emitted from the surface via the photoelectric effect. Now we change our source light to 450 nm at the same intensity level. Which of the following is the result from the 450 nm light source compared to the 500 nm source? 1. The same number of electrons would be emitted, but they would have a higher velocity correct 2. Fewer electrons would be emitted from the surface. 3. More electrons would be emitted from the surface. 4. No electrons would be emitted from the surface. 5. The same number of electrons would be emitted, but they would have a lower velocity Explanation: 500 nm light has more energy than than the work function of potassium due to the fact that electrons were emitted. Therefore 450 nm light, which is higher in energy than the 500 nm light, will also emit electrons. The number of electrons emitted must be the same...
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This note was uploaded on 03/10/2011 for the course CHEM 301 taught by Professor Wandelt during the Fall '08 term at University of Texas.
- Fall '08