C10J - Structure and Bonding
Problem Paper #1 (Week of Oct. 29, 2001)

1.        Use the data below to calculate the Si-Si bond energy!
        c Si = 1.7
        c O = 3.5
        Si-O = 466 kJ/mol
        O-O = 146 kJ/mol
        Si-Si = ?? kJ/mol

2.        Using Slater's rules, calculate:

     (a) the effective nuclear charge, Z* , felt by an electron in the second quantum number level of the K atom.

     (b) the value of Z* felt by an electron in the 3s subshell of atoms of Na and Cl.

3. Use the Allred/Rochow method along with relevant data from 'Basic Inorganic Chemistry' to calculate Z*, for a valence electron in the Si and S atoms.

4.        Give the Lewis structures for these molecules/ions:
     (i) CH3OH      (ii) ClO4-      (iii) H2SO4      ( iv) NHS2O62-      (v) S2O72-      (vi) H3PO2      (vii)SO52-

5. Deduce the geometry of each of the following:     SO2;     P(CH3)3;     XeF3+;     AsH3;     B(OH)4-;     XeF4;     Zn(NH3)4 2+;     BrF5;     AsF5.

6.    (a) Explain why some bond angles in AX5E type molecules are less than 90O.
    (b) Explain the trend observed for the bond angles in compounds of P:     PI3, 102;
     PBr3, 101.1;     PCl3, 100.3;     PF3, 97.8O.

7. (a) Which symmetry elements generate only one operation?
(b) List all operations generated by the symmetry elements C3 , C4 and C5.
(c) List all the symmetry elements of : ICl4-; CHCl3 ; H2CO

Answers to Problem Paper #1
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