Intensive Chemistry Seminar – Fall 2007
worksheet #9
1. Show the Lewis dot structures for reactants and products in the formation of table salt.
2. Draw the Lewis dot structure of water with its respective partial positive and negative charges.
3. What is the equation used to calculate formal charge of an atom in a molecule? Use this equation to calculate the formal charges of each atom in the following molecules: C ≡ O, NO2-, CaCl2 and NH3Cl. (It might be helpful to draw out a couple of these in Lewis dot structures.)
4. Name the four elements that most commonly use multiple bonds to fulfill their octet.
5. True and False (answer and explain)
1. Lewis dot structures provide information about the geometric shape of a molecule.
2. A neutral molecule can have atoms of different formal charges. Give an example to support your claim
3. A resonance structure illustrates the oscillations of distinct electrons back and fourth between different bonding structures.
4. In order to be stable an atom must have the electron configuration of a noble gas
6. Draw both of the resonance forms for CH2CHO – along with the respective formal charges on each atom.
7. Which of the resonance structures in the previous questions do you think is more stable? Explain why. (Hint: consider their electronegativities)
8. Draw the resonance structures for O3. What is the bond order of this molecule?
9. What is the central idea behind the VSPER theory? How will VSPER enable you to determine molecular geometries?
10. Draw and name the arrangement of 2, 3, 4, 5, and 6 electron pairs located around a central atom.
11. What is the steric number? For steric numbers 2-6 name the corresponding geometry.
12. How does the presence of a lone pair affect the geometry of a molecule? Does the description of the molecular geometry make reference to the lone pairs?
13. How does the presence of two types of outer atoms affect molecular geometry?
14. We can use the same notion of a dipole moment for a diatomic molecule to create dipole moments for polyatomic molecules. Using arrows as dipole moments, draw both the individual dipole moments and the total dipole moment of the following: CO, H2O, PF5.
15. What is the difference between polar and nonpolar?