Formal Charge Practice Worksheet Answer Key

Formal Charge Practice Worksheet Answer Key:

 

Assign all formal charges in the following molecules:

Formal Charge = (# electrons atom wants) – (# electrons atom has)

1.

C: (4 electrons) – (5 electrons) = -1

3 bonds = 3 total electrons, 1 electron/bond

1 lone pair = 2 electrons

N: (5 electrons) – (5 electrons) = 0

3 bonds = 3 total electrons, 1 electron/bond

1 lone pair = 2 electrons

 

 

2.

C: (4 electrons) – (4 electrons) = 0

2 bonds = 2 total electrons, 1 electron/bond

1 lone pair = 2 electrons

N: (5 electrons) – (6 electrons) = -1

2 bonds = 2 total electrons, 1 electron/bond

2 lone pairs = 4 total electrons, 2 electrons/lone pair

 

 

3.

C1: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C2: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

O: (6 electrons) – (6 electrons) = 0

2 bonds = 2 total electrons, 1 electron/bond

2 lone pairs = 4 total electrons, 2 electrons/lone pair

N: (5 electrons) – (5 electrons) = 0

3 bonds = 3 total electrons, 1 electron/bond

1 lone pair = 2 total electrons, 2 electrons/lone pair

 

 

4.

B: (3 electrons) – (4 electrons) = -1

4 bonds = 4 total electrons, 1 electron/bond

 

 

5.

O: (6 electrons) – (7 electrons) = -1

1 bond = 1 electron

3 lone pairs = 6 electrons, 2 electrons/lone pair

 

 

6.

C1: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C2: (4 electrons) – (3 electrons) = 0

3 bonds = 3 total electrons, 1 electron/bond

C3: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

O: (6 electrons) – (7 electrons) = -1

1 bond = 1 electron

3 lone pairs = 6 total electrons, 2 electrons/lone pair

 

 

7.

C: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

O1: (6 electrons) – (6 electrons) = 0

2 bonds = 2 total electrons, 1 electron/bond

O2-3: (6 electrons) – (7 electrons) = -1

1 bond = 2 electrons, 1 electron/bond

3 lone pairs = 6 total electrons, 2 electrons/lone pair

 

 

8.

N: (5 electrons) – (4 electrons) = +1

4 bonds = 4 total electrons, 1 electron/bond

O1: (6 electrons) – (6 electrons) = 0

2 bonds = 2 total electrons, 1 electron/bond

2 lone pairs = 4 total electrons, 2 electrons/lone pair

O2: (6 electrons) – (7 electrons) = -1

1 bond = 1 electron

3 lone pairs = 6 total electrons, 2 electrons/bond

O3: (6 electrons) – (6 electrons) =0

2 bonds = 2 total electrons, 1 electron/bond

2 lone pairs = 4 total electrons, 2 electrons/lone pair

 

 

9.

C1: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C2: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

O: (6 electrons) – (6 electrons)

2 bonds = 2 total electrons, 1 electron/bond

2 lone pairs = 4 total electrons, 2 electrons/lone pair

N1: (5 electrons) – (6 electrons) = -1

2 bonds = 2 total electrons, 1 electron/bond

2 lone pairs = 4 total electrons, 2 electrons/lone pair

N2: (4 electrons) – (5 electrons) = +1

4 bonds = 4 total electrons, 1 electron/bond

N3: (5 electrons) – (5 electrons) = 0

3 bonds = 3 total electrons, 1 electron/bond

1 lone pair = 2 total electrons, 2 electrons/lone pair

 

 

10.

C1: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C2: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C3: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C4: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

O: (6 electrons) – (6 electrons) = 0

2 bonds = 2 total electrons, 1 electron/bond

2 lone pairs = 4 total electrons, 2 electrons/lone pair

N: (5 electrons) – (5 electrons) = 0

3 bonds = 3 total electrons, 1 electron/bond

1 lone pair = 2 total electrons, 2 electrons/lone pair

 

 

11.

C1: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C2: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C3: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C4: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

O: (6 electrons) – (6 electrons) = 0

2 bonds = 2 total electrons, 1 electron/bond

2 lone pairs = 4 total electrons, 2 electrons/lone pair

 

 

12.

C1: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C2: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C3: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C4: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

O: (6 electrons) – (5 electrons) = +1

3 bonds = 3 total electrons, 1 electron/bond

1 lone pair = 2 total electrons, 2 electrons/lone pair

 

 

13.

C1-6: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

O: (6 electrons) – (7 electrons) = -1

1 bond = 1 electron

3 lone pairs = 6 total electron, 2 electrons/lone pair

 

 

14.

C1: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C2: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C3: (4 electrons) – (5 electrons) = -1

N: (5 electrons) – (4 electrons) = +1

 

 

15.

C1: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

C2: (4 electrons) – (4 electrons) = 0

N: (5 electrons) – (4 electrons) = +1

4 bonds = 4 total electrons, 1 electron/bond

O: (6 electrons) – (7 electrons) = -1

1 bond = 1 electron

3 lone pairs = 6 total electrons, 2 electrons/lone pair

 

 

16.

C1: (4 electrons) – (5 electrons) = -1

3 bonds = 3 total electrons, 1 electron/bond

1 lone pair = 2 electrons

C2-6: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

O: (6 electrons) – (6 electrons) = 0

2 bonds = 2 total electrons, 1 electron/bond

2 lone pairs = 4 total electrons, 2 electrons/lone pair

 

 

17.

C1: (4 electrons) – (3 electrons) = +1

3 bonds = 3 total electrons, 1 electron/bond

C2-6: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

 

 

18. 

O1: (6 electrons) – (5 electrons) = +1

3 bonds = 3 total electrons, 1 electron/bond

1 lone pair = 2 electrons

O2: (6 electrons) – (7 electrons) = -1

1 bond = 1 electron

3 lone pairs = 6 total electrons, 2 electrons/lone pair

O3: (6 electrons) – (7 electrons) = -1

1 bond = 1 electron

3 lone pairs = 6 total electrons, 2 electrons/lone pair

S: (6 electrons) – (5 electrons) = +1

3 bonds = 3 total electrons, 1 electron/bond

1 lone pair = 2 electrons

N1: (5 electrons) – (5 electrons) = 0

3 bonds = 3 total electrons, 1 electron/bond

1 lone pair = 2 electrons

N2: (5 electrons) – (4 electrons) = +1

4 bonds = 4 total electrons, 1 electron/bond

C1: (4 electrons) – (3 electrons) = +1

3 bonds = 3 total electrons, 1 electron/bond

All non-labeled carbon atoms: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

 

 

19.

Cl1-2: (7 electrons) – (7 electrons) = 0

1 bond = 1 electron

3 lone pairs = 6 total electrons, 2 electrons/lone pair

S: (6 electrons) – (5 electrons) = +1

3 bonds = 3 total electrons, 1 electron/bond

1 lone pair = 2 electrons

O: (6 electrons) – (7 electrons) = -1

1 bond = 1 electrons

3 lone pairs = 6 total electrons, 2 electrons/lone pair

 

 

20.

C1-7: (4 electrons) – (4 electrons) = 0

4 bonds = 4 total electrons, 1 electron/bond

N: (5 electrons) – (4 electrons) = +1

4 bonds = 4 total electrons, 1 electron/bond

O: (6 electrons) – (5 electrons) = +1

3 bonds = 3 total electrons, 1 electron/bond

1 lone pair = 2 electrons