which electrons do lewis structure show?
Lewis Structures for O-chem « reactions & distractions
Being able to draw Lewis structures is an important skill in organic chemistry. Being able to draw Lewis structures quickly and easily is invaluable. In this article, I will outline a few different methods for drawing Lewis structures, and you can decide for yourself which is easiest.
If you are taking an undergraduate organic chemistry class, I'm assuming you've already had some experience with drawing Lewis dot diagrams from Gen. Chem. Therefore, I'm only going outline the basic steps for each method but won't go into any great detail beyond that.
Method #1: The "dot" method (aka, the "jigsaw puzzle" method)
In this method, you place dots (representing the valence electrons) around each atom in the compound, and then piece them together (like a jigsaw puzzle) until all atoms have their octet rule satisfied (2e- around any Hydrogens, 8e- around most other 2nd-row elements, except Boron. Boron is weird.)
1. Draw all the atoms in the compound with dots representing valence electrons:
NOTE: If you are dealing with ions, rather than neutral compounds, you must remember to add in or subtract out the appropriate number of electron "dots" in order to make this work.
2. Put the atoms together by electron pairs. That is, arrange the atoms with their dots such that all the atoms are joined together with two dots in between (one from each atom). When you pair up two electrons from two different atoms, those electrons will form a bond, which can be re-drawn as a line. Electrons on atoms which are not part of bonds remain as dots (as with N, O, and F in the chart below.)
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