CHM 1046C                                                              Name:___Answers________

Module 4iii - Part Q: Formal Charge             1 point

1.    Using the method of the octet rule, the following structure was drawn:

sulfurTrioxidez

 

 

Assign the formal charge to each atom in the Lewis Structure
by completing the table below:

 

Show the nonzero formal charges on the Lewis structure by

Placing them in circles alongside the atoms

 

 

Formal

Charge

=

Valence

Electrons

-

Nonbonding

Val Electrons

-

Bonding e1-

        2

=

Total   

S

=

6

-

0

-

4

=

+2

O-

=

6

-

6

-

1

=

-1

O=

=

6

-

4

-

2

=

0

O-

=

6

-

6

-

1

=

-1

        

         Sum of the formal charges in the molecule =  __0__

 

2.    Using the method of the formal charge, the following structure was drawn:

VSEPRdotSO3Stick

 

 

Assign the formal charge to each atom in the Lewis Structure
by completing the table below:

 

Show the nonzero formal charges on the Lewis structure by

Placing them in circles alongside the atoms

 

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___

 

Explain why the structure in #2 is more preferred than #1!

Structure #2 has no formal charges on any atom, while structure #1 has two negative charges and one positive charge on three of the four atoms. Both give a net formal charge of zero and are feasible structures, but #1 has three positive and negative charges from something that is electrically neutral which results in a higher potential energy. In general the lower the potential energy the more stable is the structure. #2 is preferred!

3.Using the method of the octet rule, the following structure was drawn:

VSEPRdotH2SO4stick

 

 

Assign the formal charge to each atom in the Lewis Structure
by completing the table below:

 

Show the nonzero formal charges on the Lewis structure by

Placing them in circles alongside the atoms

 

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____

 

4.    Using the method of the octet rule, the following structure was drawn:

 

 

Assign the formal charge to each atom in the Lewis Structure
by completing the table below:

 

Show the nonzero formal charges on the Lewis structure by

Placing them in circles alongside the atoms

 

Formal

Charge

=

Valence

Electrons

-

Nonbonding

Val Electrons

-

Bonding e1-

        2

=

Total   

S

=

6

-

0

-

4

=

+2

-O-

=

6

-

4

-

2

=

0

H-

=

1

-

0

-

1

=

0

O-

=

6

-

6

-

1

=

-1

-O-

=

6

-

4

-

2

=

0

H-

=

1

-

0

-

1

=

0

O-

=

6

-

6

-

1

=

-1

 

         Sum of the formal charges in the molecule =  __0___

 

Explain why the structure in #4 is more preferred than #3!

#3 has no formal charges on any atom; while #4 has two negative and one positive charge on three of the 7 atoms. Both are feasible, but #4 has higher potential energy than #3.