Commonly Tested Lewis Structures

We draw Lewis Structures to predict:

-the shape of a molecule.

-the reactivity of a molecule and how it might interact with other molecules.

-the physical properties of a molecule such as boiling point, surface tension, etc.

Drawing the Lewis Structure for I3-

Video: Drawing the Lewis Structure for I3-

For the I3- Lewis structure we first count the valence electrons for the I3- molecule using the periodic table. Once we know how many valence electrons there are in I3- we can distribute them around the central atom and attempt to fill the outer shells of each atom.

For I3- we'll end up with 6 additional valence electrons after filling the octets on the outside iodine atoms. We'll just put these on the central atom since that's the only place left for them to go.

For the Lewis structure for I3- you have to take formal charges into account to find the best Lewis structure for the molecule.

You should put brackets with an negative sign around the I3- Lewis structure when you are finished drawing the structure.

It is helpful if you:

  • Try to draw the I3- Lewis structure before watching the video.
  • Watch the video and see if you missed any steps or information.
  • Try structures similar to I3- for more practice.

List of Lewis Structures

Acetone BF3 BH4- BrF5 BrO3- C2H2 C2H4 ClO-
CH4 ClO2- ClO2 ClO4- CO CS2 H2O H3O+
HCl HNO3 I3- ICl4- IF5 N2 N3- NH2OH
NH3 NO2- NO2 NO3- O2 OF2 PCl5 PH3
PO33- PO43- SCl2 SF4 SF6 SO3 SO42- XeF2