Drawing Lewis Structure
Unit 3_Module 7
- We know that most atoms are square structure where there is 1s +3p orbitas = 4
sides
- Exception H is a circle because it only has 1s
Ex. C2H4
1.
- Carbon-> Group 14 -> 4 valence electrons
- Hydrogen -> group 1 -> 1 valence electron
o Since we have 2 carbons = 8 electrons
o We have 4 hydrogens -> 4 electrons
o Total = 12 valence electrons = 8+4
2. Draw
- Carbon (4 valence electrons)
•
• C •
•
- Hydrogen has 1 valence electron
H•
o Then you draw 2 carbons (each with 4 dots)
o And 4 hydrogens (each with 1 dot)
3. Determine “which one is the central atom, and which one is the terminal atom?”
o Core atom has two or more unpaired electrons. Therefore, they can form two
or more bonds and link two or more atoms together like a chain.
o Terminal atoms only have one unpaired electron. Therefore, they can only
form one bond and, as such, will end a chain of atoms
i. In this example the core atom is C
ii. The terminal atom is H
- Start bond core atoms
b. C-C
c. Now each C has 3 unpaired electrons left
4. Attach the terminal atoms
o We know that each H has 1 unpaired electron
o We can attach 2 H to each C
