2. Table of Contents
What are Lewis Diagrams?
Try Some Problems
Importance of Lewis Diagrams
For more help
3. What are Lewis Diagrams?
A Lewis diagram is a representation of a molecule where dots are used to
show the valance electron* position around the atoms and lines or dot pairs
represent covalent bonds between atoms. Our goal is to get to 8 VE
surrounding the element because 8VE is stable. Hydrogen is different, it only
needs 2VE to be stable.
*Valance Electrons?
Valence electrons (VE) are the electrons in the outer shell of an atom. The
valence electrons are the ones involved in forming bonds to adjacent atoms.
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4. How to draw them?
Solve for H2O, Water.
Step 1. Determine the total numbers of valance electrons. Look at the
periodic table for help. H has 1 valance electron, and C has 6 valance
electrons.
5. Step 2.
Write the skeleton structure of the molecule and subtract the VE’s you use.
6. Step 3.
Distribute the remaining valance electrons to the elements as non-bonding
electrons so that each have 8 valance electrons, excluding Hydrogen (Hydrogen can
only have 2).
7. Try Some Problems
Try to solve these problems your self:
1. CH4
2. NH3
3. CO2
4. CH4
Click to see Answers
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8. Answers
This is what your answers should look like:
1. 2. 3. 4.
2.
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9. Importance of Lewis Diagrams
Resonance Structures
These resonance structures demonstrate the importance of Lewis Diagrams.
They show the differences in the bonds of molecules with the same atoms.
NO3
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10. For More Help
Links that may help:
Wikipedia
Chemed
Lewisdots
Schodor
Sources:
Video:
https://www.youtube.com/watch?v=MWDL5WCZBzE
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