AP Chemistry
Creating Lewis Dot Structures
By: Ryan Blankemeier
Table Of Contents
1.
2.
3.
4.
5.
Counting the number of total electrons
Finding the central atom
Connecting the atoms with single bonds
Add remaining electrons to fill sublevels
If sublevels don’t equal 8, make double
bonds or triple bonds to fill the octets
Step 1
•
•
•
•
•
Count the number of total electrons in [NO₂]⁻.
There is 1 N which has 5 electrons.
2 O’s that each have 6 electrons.
The – sign means it has one extra electron
5 + 12 + 1 = 18 total electrons
Step 2
• Find the central atom.
• It is usually the atom with less electrons,
unless it is H.
• N has fewer electrons that O, and there is only
one N, so we choose N as our central atom.
Step 3
• Connect the central atom to the remaining
atom with single bonds
• Draw single bonds as lines.
• Each single bond represents a covalent bond
of two electrons.
O N
O
Step 4
• Now we fill up the atoms’ octets with
remaining electrons.
• Each atoms should have 8 electrons.
• We have already used 4, so we have 14 left
13
14
9
10
1
2
O N O
12 11
8
7
6 5
3
4
Step 5
• If sublevels don’t equal 8, make double bonds
or triple bonds to fill the sublevels
• The O and the N have 8 electrons – good.
• But the other O only has 6.
• We can borrow two electrons from the N to
make another bond, and giving each atom 8⁻.
13
14
9
10
1
2
O N O
11 12
8
7
6 5
3
4
Final Structure
O N O
For more help check out this link:
http://www.chem.ucla.edu/harding/lewisdots.html