Cracking the SAT Chemistry Subject Test

Draw    the Lewis   diagram for CO 2.

1)  C   +   O(2)

4   +   6(2)    =   16  valence e−

2)  O           C           O

3)  O—C—O

4)

5)  20  assigned    e−  ≠   16  valence e−

16  assigned    e−  =

16  valence e− ✓

Lewis diagrams can get considerably more complex than the examples that are
shown here, but as long as you understand these fundamentals you should be
ready for the test.