Post 2 Chemical Bonding

Resonance is when more than one Lewis structure can be drawn. As such, compounds must have multiple bonds and when you move the bond (double), the neighbor must be able to take the bond like in cases where H can only have one bond and thus can't double bond.
An introduction to this is shown by chemwiki.
Also know the difference in vocab as molecular shape is the molecular geometry (shape) and electronic geometry is determined by the element (lone pairs of electrons and bonds).

Here are some links from khanacademy that go over the unit up to this point.
drawing dot structures
formal charge and dot structures
resonance and dot structures