Find That Which Is Hidden

by Kiley Lynch

One key “unspoken” skill that your instructor will expect you to know by now is one that instructors often don’t talk about. It’s seeing the things that are hidden. 

In the first week of class, the organic structures you’re given have all the bonds, lone pairs, and charges drawn out. But then, they start taking things away.

  • First they come for the hydrogens and carbons, and replace them with lines.
  • Next they come for the lone pairs, which are often omitted.
  • Finally they come for the charges, which might not be drawn at all.

In the end you’re left with a bunch of lines that might leave you scratching your head and saying “huh”? At this point it’s crucial to be able to “read” line drawings and to know that just because something isn’t drawn doesn’t mean it’s not there. You have to be able to recognize how many “hidden” hydrogens each carbon has, and to infer the number of lone pairs on an atom given the charge.

Instructors will assume you’ve developed this skill by “osmosis”.

If you don’t feel fully comfortable with this skill, spend some time working on it now! Here are some useful exercises.


Tomorrow: let’s wrap up this past week’s worth of notes.

Thanks for reading! James