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Unformatted text preview: Chem 125 Exam #3 Fall 2009 PART A. (4 Points each) 1. Which of the following statements is INCORRECT? a. In the photoelectric effect, light behaves as a wave. (Recall in the photoelectric effect a photon strikes the surface of a metal and if its frequency is high enough an electron is ejected from the metal). b. When a curve ball is throw, the ball still behaves as a particle. c. Soap bubbles reflect light of many different colors, indicating light is behaving as a wave. d. In an experiment light will behave as wave or a particle, but not both. e. The model where electrons move around the nucleus like planets move around the sun is incorrect. 2. For which orbital does the drawing to the right represent the electron density (electron cloud)? a. An s orbital. b. A p oribital. c. Only the p x oribital. d. A d orbital. e. An f orbital. 3. Which statement is CORRECT for an electron in an orbital with n = 4, l = 2 m l = 0, m s = -1/2? a. The principal quantum number is 2. b. It is a d orbital. c. It is an s orbital. d. It is an f orbital. e. The magnetic quantum, m l , is not consistent with the rest of the orbital information 4. Which of the following is the correct ground state electron configuration for niobium 3 + , Nb 3+ ? a. [Kr] 5s 2 4d 3 b. [Kr] 5s 2 4d c. [Kr] 5s 4d 3 d. [Kr] 5s 4d 2 e. [Kr] 5s 1 4d 1 2 4. , - . 2, -1, 0, 1, 2 l l means it is a d or The principle quantum is For a d orbital m bital = = [ ] 2 3 The ground state electron configurtion for the element is 5s 4d . To make a positive ion, remove electrons with the largest principle quantum number first, that is, the two 5s electrons. The next la Kr rgest principle quantum number is 4. For the same principle quantum remove in order f, d, p, and s electrons, that is, remove one of the 4d electrons. 5. How many unpaired electr a. 2 unpaired electrons; p b. 2 unpaired electrons; d c. 0 unpaired electrons; p d. 0 unpaired electrons; d e. None of the above is c 6. According to Hund’s rule, manganese, Mn? a. [[Ar] 4s ↑↓ 3d ↑↓ ↑↓ ↑ b. [Ar] 4s ↑↓ 3d ↑↓ ↑ ↑ c. [Ar] 4s ↑↓ 3d ↑ ↑ ↑ d. [Ar] 4s ↑↓ 3d ↑ ↑ ↓ e. None of the above is co 7. Which answer is closest to orbital to a 1s orbital in Li where B = 2.18 x 10-18 J a. 3 x 10 16 Hz b. 3x 10 15 Hz c. 9 x 10 15 Hz d. 2 x10-17 Hz e. It can not be determine information is given fo 8. Which of the following rea a....
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This note was uploaded on 02/04/2011 for the course CHEM 125 taught by Professor Ellis during the Spring '07 term at NJIT.
- Spring '07