I’ve finally arrived at every premed’s bane: organic chemistry. As the single most important course to be taken for the purposes of MCAT and the basis of most of medicine, I am understandably shaking in my boots.
In this post I will take Lewis Structure and Skeletal Drawing, or to the layman’s eye, squiggles and dots in space.
I will attempt to explain it as best as possible here for not only your benefit but also mine.
Lewis Structure
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The Lewis structure is used to show the placement of electrons in ionic and covalent molecules. It’s probably the first thing you were taught in any general chemistry class:
- Start with neutral atom Lewis structure and bond non-hydrogen atoms together
- Add the hydrogens
- If the valences of atoms are not satisfied, form additional bonds between atoms
- Check to see if the octet rule is satisfied for all atoms
Skeletal drawing
Every point in a drawing is a C atom with extended Hs.

A great online skeletal drawing tool is attached to the link you just read over.
Bond Remix
Atom | Number of Valence Electrons | Number of Bonds |
C | 4 | 4 |
H | 1 | 1 |
O | 6 | 2 |
N | 5 | 3 |
X* | 7 | 1 |
* X represents a halide.
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