Arkansas State University Department of Chemistry and Physics

CHEM1023                                                                        Name_______________________
Exam 2                                                                                Spring 2000

1.  Draw the Lewis Dot Structure for each of the following:  (2 points each)

 a) AlI₃                                                    b)   CO₂
 
 
 
 

 c)   SeO₃^-2                                            d)   IBr₅
 
 
 

2. Why is the H-O-H angle in H₂O less than the expected angle for its E. A.?   (4 points)
 
 
 
 
 

3. For each of the following, give the electron arrangement (E.A.) and the molecular geometry (M.G.).    (2 points each)
 

                                           E.A.                  M.G.

 a)   CCl₄
 

 b)   BrF₃
 

 c)   SO₃
 

 d)   CO₂
 

 e)   NH₃
 

4. Calculate the formal charge for each of the atoms in the compounds given below: (8 points)

 a)   CCl₄
 
 
 
 

 b)   PO₄^3-
 
 
 
 

5. Describe the bonding (ionic, covalent, polar covalent) in each of the following:       (2 points each)

                                                                         Electronegativities
 a) SO₂                                                                       F 4.0
                                                                                  O 3.5
 b) NCl₃                                                                     N 3.1
                                                                                  Cl 2.9
 c)  KF                                                                       C 2.5
                                                                                   S 2.4
 d)  CuS                                                                    Cu 1.8
                                                                                   K 0.9
 e)  CO

6.   Draw the resonance forms of  NO₃^-                 (6 points)
 
 
 

7.  Tell whether each of the following has a dipole moment or not.
 (2 points each)

 a)   NO₃^-
 

 b)   CCl₄
 

 c)   HF
 

 d)   NF₃
 
 
 

8. Describe the hybridization of each atom in 7a    (6 points)
 

 N

 O
 
 

9. Describe the bonding (s and/or p) in CO.  Include a diagram showing orbital overlap for full credit. (15 points)
 
 
 
 

10. If seven groups of electrons are on the central atom, what would be the hybrid orbitals needed to accommodate these electrons?  (5 points)
 
 
 

11. For each electron arrangement, give the angles and the hybrid orbitals?  (6 points)

a) trigonal planar
 

b) linear
 

12. Why are VSEPR Rules important?    (4 points)