Your full name (PLEASE PRINT) Second hour test page 1 of 5 October 24, 2003 Your scheduled Tuesday quiz section (please circle) B hr E hr

Transcription

1 EM 111 Your full name (PLEASE PRINT) Second hour test page 1 of 5 October 24, 2003 Your scheduled Tuesday quiz section (please circle) B hr E hr 1 Your scheduled Tuesday quiz instructor: You may use a writing implement, hand-calculator, the pink data page and your Periodic Table (unmarked, honor code) as obtained in this course. NO scratch paper is permitted! As requested of the faculty by the Student Executive ommittee, students must sit in every other seat during the test. The PROPER METOD (i.e., Problem Set 0) must be shown clearly on all problems, and final answers must be expressed in appropriate form. Pay attention to dimensions!! When blanks for answers are provided, write your answer to be graded in the blank---we may not grade answers written in other locations! It is your responsibility to make sure the test you turn in has 5 securely fastened pages.

2 1. (6 pts) Arrange the following substances in order: 2 a) Mg 2+, Ar, Br -, a 2+ in order of increasing radius: b) Na, Na +, O, Ne in order of increasing ionization energy: 2. (6 pts) ow many radial and angular nodes are associated with the following sets of quantum numbers a) n = 4, l = 1 angular: radial b) n = 2, l = 0 angular: radial c) n = 6, l = 3 angular: radial 3. (6 pts) The radiation emitted in the transition from n = 3 to n = 2 in a neutral hydrogen atom has a wavelength of nm. What would be the wavelength of radiation emitted from a doubly ionized lithium atom (Li 2+ ) if a transition occurred from n = 3 to n = 2? [Remember that E n = -(hc)r (Z 2 /n 2 )] 4. (8 pts) Give systematic names to the following compounds: (a) Al 2 O 3 (b) (N 4 ) 2 S (c) s 2 SO 4 (d) a(no 3 ) 2 5. (2 pts) Write a balanced equation for the decay of 11, which is used in positron emission tomography to scan the uptake of glucose in the body.

3 6. (8 pts) Draw pictures of the following individual orbitals (be sure to indicate phases, axes, and label and identify nodes where appropriate): 3 a) sp b) π 2 p c) 4s d) 3d xz 7. (3 pts) Identify this atomic orbital. Y (10 pts) Please fill out the table below according to the method illustrated in recitation. lo 4 electron pool? dot picture? electron pair shape? Molecular shape? (sketch and name) (show work) (draw dots clearly!) (sketch and name) ybridization? π-bonds likely? 9. (6 pts) What is the percent by weight of in formaldehyde ( 2 O)? 10. (4 pts) Which of the following combinations of quantum numbers are allowed for an electron in a oneelectron atom? ircle the letter(s) of your choice(s). (a) n = 4, l = 4, m l = 1, m s = 1/2 (b) n = 3, l = -1, m l = 2, m s = -1/2 (c) n = 7, l = 1, m l = -1, m s = 3/2 (d) n = 3, l = 1, m l = 1, m s = ½

4 11. (2 pts) Which of the following has the least favorable electron affinity? (Please circle your answer) 4 Ne Al B 12. (2 pts) Which of the following will be the most electronegative? (Please circle your answer) O l S e 13. (10pts) (a) Draw a molecular orbital energy correlation diagram below for 2 in the manner done in class and in the textbook. (b) arefully label both the atomic and molecular orbitals in your diagram ( g and u label are NOT necessary). Orbital cartoons are NOT required in your diagram. (c) Fill your diagram with the appropriate number of electrons for 2. (d) What is the bond order of 2? (e) What is the bond order of 2 +? (f) Is 2 paramagnetic? (g) Which has the higher ionization energy: 2 molecule or the atom? 14. (4 pts) What is the relationship between each pair of compounds shown below? The answer should be one of the following: constitutional isomers, conformers, enantiomers, diastereomers, or NONE. Please write your answer in the blank provided. 3 3 O (3 pts) learly circle each stereogenic center in the molecule below: O O O O O 2 O O 3

5 5 16. (20 pts) Read carefully and circle the letter of all of the statements below that are true: a) The valence bond picture is inherently a localized bonding model. b) The Self onsistent Field Approximation assumes that the nuclei are fixed. c) The range of the spherical polar coordinates isr :0, θ :0 π and φ :0. d) Radiofrequency radiation used in NMR spectroscopy causes a nuclear spin flip. e) MRI relies on the existence of a homogeneous magnetic field. f) The study of the interaction of electromagnetic radiation with matter is known as spectroscopy. g) Diastereomers have the same chemical formulas and the same properties. h) It is possible to write wavefunctions for molecular orbitals by combining atomic orbital wavefunctions. i) onstructive and destructive interference between atomic orbitals on the same atom can be used to understand the shapes and geometries of hybrid orbitals. j) onstructive and destructive interference between atomic orbitals on different atoms can be used to understand the shapes and geometries of molecular orbitals. k) In valence bond theory, the energy price of electron promotion in energy is more than compensated for by the lowering in energy due to the enhanced bonding that results. l) In the valence bond treatment of Acetylene, 2 2, the pi-bond is described as the overlap of a 2p molecular orbital on with a 2p molecular orbital on. m) For a multi-electron atom, a 2s electron experiences a different Z eff than a 2p electron. n) For NO 2 -, all of the atoms are sp 2 hybridized in valence bond theory. o) For the MO picture of pi-bonding, the energy of the orbital increases as the number of nodes increases. p) For a multi-electron atom, the energy depends only on the value of the n quantum number. PLEDGE: I have neither given nor received any unacknowledged aid on this test. Signed,