ADVANCED INORGANIC CHEMISTRY February 17, 2009 INSTRUCTIONS: PRINT YOUR NAME > NAME.

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1 ADVANCED INORGANIC CHEMISTRY QUIZ I February 17, 2009 INSTRUCTIONS: PRINT YOUR NAME > NAME. WORK 4 of the 5 problems SHOW YOUR WORK FOR PARTIAL CREDIT THE LAST PAGE IS A Periodic Table R = lit-atm/mol-k 1 (25) R = J/mol-K 2 (25) h = X J-s 3 (25) c = X 10 8 m/s 4 (25) J = (kg-m 2 )/s 2 5 (25) l TOTAL(100)

2 1. Answer the 5 of following (a)-(f). (This question goes over two pages.) (a) How did the Bohr model of the atom explain line spectra of atoms? (b) For each of the sets of quantum number, fill in the blank with all possible values (some may have more than one value or be infinite) than can replace the missing quantum number indicated by a question mark. n l m l m s possible values 3? 0 -½? 3 1 +½ 4 2? +½ 6 3-2? (c) Sketch the shape of the following orbitals. 2s 3px 3d xz 3d x 2- y 2 z z z z x x x x y y y y (d) Give the electron configuration of the following atoms or ions. You may use the noble gas short cut: F Co Br Se 2- Ba 2+ Mn 2+

3 (e) Using orbital energy level diagrams for the 3d electrons, show how many unpaired electrons are there in an atom of Ni? (f) What are paramagnetism and ferromagnetism and how do they differ?

4 2. Answer 5 the following questions (a)-(f). (a) What major event led to widespread acceptance of Mendeleev s periodic table? (b) The main group elements are distributed in the periodic table in the first two columns and the last six columns. The transition metals are found in 10 columns between the main groups. What are the sources of these numbers 2, 6, and 10? (c) What is the name for the elements in group 17 (VIIA)? Group 1A (1)? Name a transition metal in period 5 (d) Would you expect an atom of U with 88 neutrons to be stable? Why or why not? (e) The magic numbers for nucleons are 2, 8, 20, 28, 50, 82, and 126. Which of the following isotopes would you expect to be especially stable? 40 Ca 50 Cr 99 Mo 208 Pb (f) Why do most stable isotopes have an even number for the sum of protons and neutrons?

5 3. Answer the following (a)-(d). (This question goes over two pages.) (a) Rank the following from the smallest to the largest for the given property: Atomic radii Si C F < < Atomic or ionic radii S 2- S P 3- < < Ionization Energy Mg Ca Ba < < Ionization Energy Mg Mg + Mg 2+ < < (b) Write the chemical equations for the first four ionization energies of Al (IE 1, IE 2, IE 3, and IE 4 ) (c) The values for the four ionization energies of Aluminum are 577, 1815, 2740, and kj/mol, respectively. Explain why there is a general increase in the values from IE 1 to IE 4 and an especially large jump between the 3 rd and 4 th ionization energies.

6 (d) Using Slaters Rules, calculate the Z* (effective atomic number) for a 3d and 2s electron in an atom of Co. Remember, an electron does not shield itself. 1. The electronic structure of the atom is written in groupings as follows: (1s) (2s, 2p) (3s, 3p) (3d) (4s, 4p) (4d) (4f) (5s, 5p), and so on. 2. Electrons in higher orbitals (to the right in the list above) do not shield those in lower orbitals. 3. For ns or np valence electrons: a. Electrons in the same ns, np level contribute 0.35, except the 1s, where 0.30 works better. b. Electrons in the n-1 level contribute c. Electrons in the n-2 or lower levels contribute For nd and nf valence electrons: a. Electrons in the same nd or nf level contribute b. Electrons in groupings to the left contribute 1.00.

7 4. Consider the species N 2, and N 2 +,. (These species have s-p mixing) (a) Sketch energy level diagrams appropriate for these two species. Label you level with and designations N 2 N 2 + (b) Calculate the bond order of each species. (c) Rank the species in order of increasing bond length < Rank the species in order of increasing bond strength. < (d) Which if any of the three species is paramagnetic? (e) Sketch the shape of the and * orbitals.

8 5. Answer 5 of the following (a)- (f). This question goes over two pages. (a) Briefly describe how the molecular orbitals of CO differ from the molecular orbitals homonuclear diatomics (b) The fulminate ion is CNO - is isoelectronic with CO 2 The atoms are listed in the order of connectivity. The ion is not very stable. It explodes by contact or with exposure to light. Draw three resonance structures with formal charges, and explain why the ion is not stable. (c) Draw valid Lewis structures and give the name of the shape of the following molecules or ions. (The total number of electrons is given in parentheses.) (a) NF 3 (26) (b) SO 3 2- (26) (c) IBr 5 (42) (d) BrF 2 - (22) (e) NO 2 - (18)

9 (d) Which of have the higher boiling point in each of the following pairs? Explain you reasoning H 2 O and H 2 S BrF 3 and BrI 3 Br 2 and ICl (e) Name at least four distinguishing properties of metals? (f) Explain the electron sea and molecular orbital band theory models that explains metalllic bonding.