radiation is directed at an atom or molecule. Electrons are ejected from the valence shell and their kinetic energies are measured. Calculate the ionization energy (i.e., the work function) of a rubidium atom given that radiation of wavelength 58 . 4 nm produces electrons with a speed of 2450 km s - 1 . Calculate the wavelength of the electron. (b) [10 pts] An excited hydrogen atom emits light with a frequency of 1 . 141 × 10 14 Hz to reach the energy level for which n = 4. In what principal quantum level did the electron begin? (c) [10 pts] An electron in a one-dimensional box requires a wavelength of 8080 nm to excite an electron from the n = 2 to the n = 3 energy level. Calculate the length of the box. Page 7 of 10
Chem 2090 Preliminary Exam 2 April 17, 2018 6. Orbitals (a) [3 pts] What neutral atom has an electron configuration [Ne] 3 s 2 3 p 4 ? (b) [3 pts] What - 2 ion has an electron configuration [Ne]? (c) [12 pts] Draw the 3 s and 3 p x electron orbitals. Indicate the sign of the electron matter wave in each region of space. Label the nodes (angular, radial). (d) [12 pts] The first few possible electron wavefunctions in a hydrogen atom are named the s , p , d , and f orbitals. For an electron in the 5 f orbital, give the 1. principal quantum number n : 2. angular quantum number ‘ : and the 3. allowed values of the magnetic quantum number m ‘ : 4. allowed values of the spin quantum number m s : 5. number of radial nodes: 6. number of angular nodes: Page 8 of 10
Chem 2090 Preliminary Exam 2 April 17, 2018 7. Transition Metals (a) [8 pts] Consider the complex [Ag(NH 3 ) 2 ]Cl. What is the electron configuration for the silver ion in this complex? (b) [10 pts] The above silver complex has a linear bonding geometry. Taking the NH 3 ligands to be located along the + z and - z axis, draw a d -orbital energy level diagram for the d -electrons in the complex. (c) [12 pts] A scientist wishes to determine if a newly discovered neutral ligand, X, produces high-spin or low-spin octahedral complexes. She has available samples of the compounds [Fe(X) 6 ]Cl 2 (s) and [Ni(X) 6 ]Cl 2 (s). Which, if either, of these compounds is better suited for this analysis? Why?
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