1. Electron Dot and Structual Diagrams for Covalent Compounds

2. Lewis Structures
Structural Diagrams show the number of bonds in a compound.
Electron Dot Diagrams show the electrons involved in the bonds of compounds. H - O H : O
Non-bonding e- or lone pairs
Bonding e-
1 pair of electrons = 1 bond

3. Electron Dot Diagrams
Determine the number of valence e- for an element.

4. 7e-
8e-
1e-
valence electrons
2e-
3e-
4e-
5e-
6e-

5. Electron Dot Diagrams
Determine the number of valence e- for an element.
H Cl F S O P N C Si
# valence e H . Cl : . F : . : S . : O . . P : . N : . C . Si
# of bonds
When drawing structural diagrams, each element must have the correct number of bonds.

6. Electron Dot Diagrams
Each bond in the structural formula represents two electrons.
All valence electrons must be used
Each element must have a full valence orbital (8e-) , except H (2e-)
Try C2H6

7. First, determine the central atom (the one with the most bonding electrons):
Carbon 4 e-
Hydrogen 1 e-
So the central atoms will be? C

8. Electron Dot Diagrams
C2H6 . C . . .

9. Electron Dot Diagrams
C2H6 . . . . C C . . . .

10. H H . . . . . . . . H . H . . . . . H H Electron Dot Diagrams C C C2H6
All atoms have a full shell

11. H H . . . . . . . . H . H . . . . . H H Electron Dot Diagrams C C C2H6
All atoms have a full shell

12. Electron Dot Diagrams H C
A structural diagram is one that shows each bond as a line. Each line represents 2 bonding electrons.
Lone pairs are not shown in a structural diagram
C2H6 C H

13. Electron Dot Diagrams
HCN

14. Electron Dot Diagrams
HCN

15. Electron Dot Diagrams
HCN H C N

16. Electron Dot Diagrams
HCN . . . . H C .

17. Electron Dot Diagrams
HCN . . . . H C . N . . .

18. C H N . . . . . H . N . . . . Electron Dot Diagrams HCN C
Atoms have full shells
All valence electrons were used

19. Electron Dot Diagrams
Try drawing the electron dot diagram for:
CO2

20. O C O Electron Dot Diagrams Try drawing the electron dot diagram for:

21. . . . . . . . . . . O . . . O . . . Electron Dot Diagrams
Try drawing the electron dot diagram for:
CO2 . . . . . . . . . . C O . . . O . . .
Atoms have full shells
All valence electrons were used

22. C O . . . . . . . . . . O . . . O . . . Electron Dot Diagrams
Try drawing the electron dot diagram for:
CO2 C O . . . . . . . . . . C O . . . O . . .
Atoms have full shells
All valence electrons were used

23. Electron Dot Diagrams
Try drawing the electron dot diagram for: N2

24. Electron Dot Diagrams
Try drawing the electron dot diagram for: N2
N N

25. . . . . . N N . . . . . Electron Dot Diagrams
Try drawing the electron dot diagram for: N2 . . . . . N N . . . . .
Atoms have full shells
All valence electrons were used

26. N . . . . . N N . . . . . Electron Dot Diagrams
Try drawing the electron dot diagram for: N2 N . . . . . N N . . . . .
Atoms have full shells
All valence electrons were used

27. Electron Dot Diagrams Try drawing the electron dot diagram for:
P2O3 (sym)

28. O P O P O Electron Dot Diagrams
Try drawing the electron dot diagram for:
P2O3
O P O P O
Hint: This molecule is symmetrical…which means an O will be in the center.

29. Electron Dot Diagrams
Try drawing the electron dot diagram for:
P2O3 . . . . . . . . . . . . . . . . . . O P . . . O P O . . . . . . .

30. Electron Dot Diagrams
Try drawing the electron dot diagram for:
P2O3 P O . . . . . . . . . . . . . . . . . . O P . . . O P O . . . . . . .

31. Electron Dot Diagrams Try drawing the electron dot diagram for:
C4H8 (cyclic)

32. Electron Dot Diagrams
Try drawing the electron dot diagram for:
C4H8 (cyclic) H H . . . . . . . . C C H H . . . . . . . . H . C . . C . H . . . . H H

33. H H C C H H H C C H H H Electron Dot Diagrams
Try drawing structural diagrams for the
following: C4H8 (cyclic) H H C C H H H C C H H H