Module
Four III: Part B1 Dot Structures via Formal Charge 7 points
Using
a periodic chart draw the electron dot/stick structures of the following
molecules. Use the method of formal charges to show the best structure: (Steric Numbers 2-6)
H2SO4 Sulfuric Acid
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val
Electrons |
- |
Bonding
e1- 2 |
= |
Total |
S |
= |
6 |
- |
0 |
- |
6 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
Sum of the formal charges in the
molecule = __0____
Best:
Not Best via Octet:
Formal Charge all atoms = 0; total = 0 Best
Structure
H2SO3 Sulfurous
Acid
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val
Electrons |
- |
Bonding
e1- 2 |
= |
Total |
S |
= |
6 |
- |
2 |
- |
4 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
Sum of
the formal charges in the molecule = __0____
Best: Not Best via Octet:
Formal Charge all atoms = 0; total = 0 Best
Structure
H3PO4 Phosphoric Acid
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
||||
P |
= |
5 |
- |
0 |
- |
5 |
= |
0 |
||||
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
||||
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
||||
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
||||
Sum of
the formal charges in the molecule = __0____
Best:Not Best vis Octet:
Formal Charge all atoms = 0; total = 0 Best Structure
H3PO3 Phosphonic Acid versus Phosphorous acid
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
||||
P |
= |
5 |
- |
0 |
- |
5 |
= |
0 |
||||
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
||||
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
||||
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
||||
Sum of
the formal charges in the molecule = __0____
Best: Not Best
vis Octet:
Formal Charge all atoms = 0; total = 0 Best Structure
HClO4
Perchloric Acid
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
||||
Cl |
= |
7 |
- |
0 |
- |
7 |
= |
0 |
||||
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
||||
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
Sum of
the formal charges in the molecule = __0____
Best:
Not Best Via Octet
Formal Charge all atoms = 0; total = 0 Best
Structure
HClO3
Chloric Acid
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
||||
Cl |
= |
7 |
- |
0 |
- |
7 |
= |
0 |
||||
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
||||
Sum of
the formal charges in the molecule = __0____
Best: Not
Best Via Octet:
Formal Charge all atoms = 0; total = 0 Best
Structure
HClO2
Chlorous Acid
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
||||
Cl |
= |
7 |
- |
4 |
- |
3 |
= |
0 |
||||
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
||||
Sum of
the formal charges in the molecule = __0____
Best: Not Best Via Octet:
Formal Charge all atoms = 0; total = 0 Best
Structure
HClO HypoChlorous Acid
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
||||
Cl |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
||||
-O- |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
||||
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
||||
Sum of
the formal charges in the molecule = __0____
Octet Rule produces Best Structure
Formal Charge all atoms = 0; total = 0 Best Structure
SO2
Sulfur Dioxide
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val
Electrons |
- |
Bonding
e1- 2 |
= |
Total |
S |
= |
6 |
- |
0 |
- |
6 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
Best: Not Best Via Octet:
Formal Charge all atoms = 0; total = 0 Best
Structure
SO3 Sulfur
Trioxide
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val
Electrons |
- |
Bonding
e1- 2 |
= |
Total |
S |
= |
6 |
- |
0 |
- |
6 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
Sum of the formal charges in the
molecule = ___0___
Best: Not Best
Via Octet:
Formal Charge all atoms = 0; total = 0 Best Structure
AsF5 Arsenic Pentafluoride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
As |
= |
5 |
- |
0 |
- |
5 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___0___
Formal Charge all atoms = 0; total = 0 Best
Structure
SF6 Sulfur
Hexafluoride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
S |
= |
6 |
- |
0 |
- |
6 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___0___
Best:
Formal Charge all atoms = 0; total = 0 Best
Structure
SF4 Sulfur Tetrafluoride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
S |
= |
6 |
- |
2 |
- |
4 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___0___
Best:
Formal Charge all atoms = 0; total = 0 Best
Structure
SbCl5 Antimony Pentachloride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
Sb |
= |
5 |
- |
0 |
- |
5 |
= |
0 |
Cl- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___0___
Formal Charge all atoms = 0; total = 0 Best
Structure
PCl5 Phosphorus Pentachloride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
P |
= |
5 |
- |
0 |
- |
5 |
= |
0 |
Cl- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___0___
Formal Charge all atoms = 0; total = 0 Best
Structure
PCl3 Phosphorus Trichloride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1- 2 |
= |
Total |
P |
= |
5 |
- |
0 |
- |
5 |
= |
0 |
Cl- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___0___
Octet Rule prduces Best Structure
Formal Charge all atoms = 0; total = 0 Best
Structure
PCl61- Phosphorus Hexachloride Ion
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
P |
= |
5 |
- |
0 |
- |
6 |
= |
-1 |
Cl- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___-1___
(Not
Possible using Octet Rule)
Formal Charge on Phosphorus atom = -1
Total
Formal Charge = -1; Polyion
Charge = -1
All Chlorine atoms formal charge = 0
Best
Structure
SeF6 Selenium
Hexafluoride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
Se |
= |
6 |
- |
0 |
- |
6 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___0___
Formal Charge all atoms = 0; total = 0 Best
Structure
HArF Argon Fluorohydride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
Xe |
= |
8 |
- |
6 |
- |
2 |
= |
0 |
H- |
= |
1 |
- |
0 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___0___
Formal Charge all atoms = 0; total = 0 Best
Structure
Br31- TriBromide
Ion
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
Br- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Br- |
= |
7 |
- |
6 |
- |
2 |
= |
-1 |
Br- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___-1___
(Not Possible using Octet Rule)
Formal Charge on middle Bromine atom = -1
Total
Formal Charge = -1; Polyion
Charge = -1
Other two bromine (each side) atoms formal charge = 0
Best
Structure
I31- TriIodide Ion
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
I- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
I- |
= |
7 |
- |
6 |
- |
2 |
= |
-1 |
I- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___-1___
(Not Possible using Octet Rule)
Formal Charge on middle Iodine atom = -1
Total
Formal Charge = -1; Polyion
Charge = -1
Other two Iodine (each side) atoms formal charge = 0
Best
Structure
KrF2 Krypton Difluoride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
Kr |
= |
8 |
- |
6 |
- |
2 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___0___
Formal Charge all atoms = 0; total = 0 Best
Structure
XeF4 Xexon Tetrafluoride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
Xe |
= |
8 |
- |
4 |
- |
4 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___0___
Formal Charge all atoms = 0; total = 0 Best
Structure
XeO4 Xexon Tetroxide
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
Xe |
= |
8 |
- |
4 |
- |
4 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
Sum of the formal charges in the molecule = ___0___
Formal
Charge all atoms = 0; total = 0 Best Structure
BrF3
Bromine Trifluoride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
Br |
= |
7 |
- |
4 |
- |
3 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of
the formal charges in the molecule = ___0___
(Not Possible using Octet Rule)
Formal Charge all atoms = 0; total = 0 Best
Structure
BrF41+ Bromine
Tetrafluoride Ion
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
Br |
= |
7 |
- |
2 |
- |
4 |
= |
+1 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the Polyion = ___+1___
(Not Possible using Octet Rule)
Formal Charge on Bromine atom = +1
Total Formal
Charge = +1; Polyion Formal Charge = +1
All Fluorine atoms formal charge = 0
Best Structure
BrF5 Bromine Pentafluoride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
Br |
= |
7 |
- |
2 |
- |
5 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
F- |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of
the formal charges in the molecule = ___0___
(Not Possible using Octet Rule)
Formal Charge all atoms = 0; total = 0 Best
Structure
SO2Cl2 Sulfuryl Chloride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
S |
= |
6 |
- |
0 |
- |
6 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
O= |
= |
6 |
- |
4 |
- |
2 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Cl - |
= |
7 |
- |
6 |
- |
1 |
= |
0 |
Sum of the formal charges in the molecule = ___0___
Formal Charge all atoms = 0; total = 0 Best
Structure
Reading
Reference: Sections 8.5 Octet Rule and 8.7 Formal Charge (page 374)
Reference
Octet Rule: B. Dot Structures of Covalent Compounds Section
2.10, 6.6, 7.1, 7.5, 7.6
Octet Rule
Answers: http://www.fccj.us/chm2045/SampleTest/45M4bAnswers.htm
Other
Ions/Compounds to consider which may be the exam question:
ClF5
AsF61-
SeF4 PF3Cl2
ClF5 Chlorine Pentafluoride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
Cl |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
Sum of
the formal charges in the molecule = _______
SeF4 Selenium Tetrafluoride
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
Se |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
Sum of
the formal charges in the molecule = _______
PF3Cl2
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
P |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
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|
|
|
|
F- |
|
|
|
|
|
|
|
|
Cl- |
|
|
|
|
|
|
|
|
Cl- |
|
|
|
|
|
|
|
|
Sum of
the formal charges in the molecule = _______
AsF61- Arsenic
Hexafluoride Ion
Formal Charge |
= |
Valence Electrons |
- |
Nonbonding Val Electrons |
- |
Bonding e1-
2 |
= |
Total |
As |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
F- |
|
|
|
|
|
|
|
|
Sum of
the formal charges in the molecule = _______