1. Drawing Lewis Structures (electron dot diagrams)
4.1

2. Drawing Lewis Structures Step #1
Decide which atoms are bonded The central atom is usually more metallic, or less electronegative not usually oxygen, never hydrogen

3. Drawing Lewis Structures Step #2
Count the valence electrons you have, add or subtract electrons according to charge of polyatomic ions.

4. Drawing Lewis Structures Step #3
Place 2 electrons in each bond between atoms (remember that they all will have at least a single bond)

5. Drawing Lewis Structures Step #4
Complete the octets of the atoms attached to the central atom, by adding lone pairs. Place any remaining electrons on the central atom, in pairs

6. Drawing Lewis Structures Step #5
If the central atom does not have an octet, form double or triple bonds

7. Drawing Lewis Structures Step #6
Draw the Lewis structure and enclose polyatomic ions within square brackets showing ion charge

8. Drawing Lewis Structures
Examples: HClO3 and SO3

10. Non-Octet Compounds
Some compounds will contain central atoms that do not follow the octet rule.
The four possibilities for non-octet compounds are:
Where more than 4 atoms are bonded to the central atom such as PCl5.
A noble gas is participating in bonding such as XeF4.
Where the central atom has less than 8 valence electrons such as BH3.
Where molecules contain an odd number of nonbonding electrons such as NO.