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 H₃O⁺

Video: Drawing the Lewis Structure for H₃O⁺

For the H3O+ Lewis structure we first count the valence electrons for the H3O+ molecule using the periodic table. Once we know how many valence electrons there are in H3O+ we can distribute them around the central atom and attempt to fill the outer shells of each atom.

When we are done adding valence electrons we check each atom to see if it has an octet (full outer shell). We also need to check to make sure we only used the number of available valence electrons we calculated earlier.

There are 8 valence electrons for the H3O+ Lewis structure.

Note that the + sign in the Lewis structure for H3O+ means that we have lost a valence electron. Therefore we only have 8 valence electrons for the H3O+ Lewis structure.

H3O+ is an important compound in Acid-Base chemistry and is considered an acid.

It is helpful if you:

• Try to draw the H₃O⁺ Lewis structure before watching the video.
• Watch the video and see if you missed any steps or information.
• Try structures similar to H₃O⁺ 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
XeF4