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Quantum Mechanics and Atomic Theory Chapter 12 E-mail: [email protected] Web-site: http://clas.sa.ucsb.edu/staff/terri/ Quantum – ch 12 1. A photon has a frequency (v) of 5.45 x 108 MHz a. Calculate the photons wavelength (λ) in nm b. What type of light is the photon? c. Calculate the energy (in J) of one photon and for one mole of photons (kJ/mol) Quantum – ch 12 2. Determine the following: a. Higher frequency: b. Higher Energy: c. Longer wavelength: IR or X-Rays or yellow or UV Microwaves purple Quantum – ch 12 3. Consider the following transitions. Which will emit light with a longer wavelength? a. n = 4 n = 2 or n=3 n=2 b. n = 3 n = 1 or n=1 n=3 c. n = 5 n = 3 or n=3 n=1 Quantum – ch 12 4. Calculate the wavelengths (nm) emitted for the following electronic transitions in a hydrogen atom. a. n = 5 n = 3 b. n = 3 n = 1 c. How would your answers vary if the electronic transitions were for Ne9+? Quantum – ch 12 5. An excited hydrogen atom with an electron in n = 5 state emits light having a frequency of 6.9 x 1014 s-1. Determine the principal quantum level (n) for the final state in this electronic transition. Quantum – ch 12 6. The figure below represents part of the emission spectrum for a oneelectron ion in the gas phase. All of the lines result from electronic transitions from excited states to the n = 3 state. A B Wavelength a. What electronic transitions correspond to lines A and B? b. If the wavelength of line B is 142.5 nm, calculate the wavelength of line A. Quantum – ch 12 7. An electron is excited from the ground state to the n = 3 state in a hydrogen atom. Which of the following statements are true? a. It takes more energy to ionize the electron from n= 3 than from the ground state. b. The electron is farther form the nucleus on average in the n = 3 state than in the ground state c. The wavelength of light emitted if the electron drops from n = 3 to n = 2 is shorter than the wavelength of light emitted if the electron falls from n = 3 to n = 1. d. The wavelength of light emitted when the electron returns to the ground state from n = 3 is the same as the wavelength absorbed to go from n = 1 to n = 3. Quantum – ch 12 8. Calculate the energy (in kJ/mol) required to remove the electron in the ground state for each of the following one-electron species. a. H b. Fe25+ c. Account for the differences Quantum – ch 12 9. The ionization energy of gold is 891 kJ/mol. Calculate the maximum wavelength (nm) of light require to remove an electron. Quantum – ch 12 10. It takes 208.4 kJ of energy to remove 1 mol of electrons from the atoms on the surface of rubidium metal. If rubidium metal is irradiated with 254-nm light, what is the maximum kinetic energy the released electrons can have? Quantum – ch 12 11. Compare the wavelengths of an electron (9.11 x 10-31 kg) traveling at 5 x 107 m/s to a 2.50 kg ball traveling at 40. m/s. Quantum – ch 12 12. Which of the following sets of quantum numbers are unacceptable? Explain your answers. a. (1, 0, 1/2, -1/2) b. (3, 0, 0, 1/2) c. (2, 2, 1, 1/2) d. (3, 2, 1, 1) e. (4, 3, -2, 1/2) Quantum – ch 12 13. How many electrons in any one atom can have the following quantum numbers? a. n = 5 b. n = 6, l = 0 c. n = 4, l = 2 d. n = 3, ml = 1 e. n = 4, l = 3, ml = -2 f. n = 2, l = 0, ml = 0, ms = -1/2 Quantum – ch 12 14. Fill in the following table: Element P Tc Cr Ag Br – Fe3+ Ground State Electron Configuration Number of Valence Electrons Number of Unpaired Electrons Quantum – ch 12 15. Determine if each of the following corresponds with an excited state or ground state electron configuration. a. [Ar]4s24p5 b. [Kr]6s1 c. [Ne]3s23p4 Quantum – ch 12 16. Which of the following has the largest radius? a. Al or Si b. F or Cl c. S or S2d. K or K+ Quantum – ch 12 17. Which of the following has the greatest ionization energy? a. K or Ca b. P or As c. Sr or Sr2+ Quantum – ch 12 18. Which of the following has the most negative electron affinity? a. Br or Kr b. C or Si Quantum – ch 12 19. The successive ionization energies for an unknown element are: I1 = 896 kJ/mol I2 = 1752 kJ/mol I3 = 14,807 kJ/mol I4 = 17,948 kJ/mol Which family does the unknown element most likely belong?