Workbook on Bonding, Lewis Structures, VSEPR
- Answer the following questions concerning these bonds C- O, C -N, C- F, C - H: (answer without looking at any charts or tables other than Periodic Table . ie atomic radii, electron affinity, ionization energy):
- Which bond is strongest and why?
- Which bond is longest and why?
- Which bond is most polar and why?
3. Certain trends in bond formation by elements can be identified. These are shown in the table below:
|
Element
|
# of Bonds
|
# of Lone Pairs
|
|
Carbon
|
4
|
0
|
|
Nitrogen
|
3
|
1
|
|
Oxygen
|
2
|
2
|
|
Fluorine
|
1
|
3
|
|
Hydrogen
|
1
|
0
|
The number of bonds an element tends to form can be referred to as its valence, and typically corresponds to how many electrons that element needs to complete its octet. These rules will always hold true for hydrogen and fluorine, and generally will hold true for the Period 2 non- metals. However, they will not always work. The examples below illustrate this. Here, draw the best Lewis Structures for these covalent species. None of these structures are cyclical. Make sure to take into account formal charge and draw resonance structures when possible. When there are resonance structures that aren't all the same, pick the "best" one.
Chem 127 Dr. Dettmar
- a) C2F4 (precursor to Teflon) Total # Valence Electrons:
- b) COCl2 (phosgene - poison gas used in WW1) Total # Valence Electrons:
- c) CH3OH (methanol - drink it and go blind!) Total # Valence Electrons:
d) NO2+ Total number of valence electrons
e) ClO3- Total # of Valence electrons
f) H3PO4 Total # Valence Electrons: