Lewis Structures

Today in Chem, Mrs. Mandarino got the party started by showing the class how to draw Lewis Structures. 

And here are some guidelines to drawing Lewis Structures!

Step One: Count the total number of valence electrons in the compound.

Dont forget! If you are finding the structure of an ion, remember to add electrons for a negative charge and subtract electrons for a positive charge.

Step Two: Predict the arrangement of the atoms in the molecule, drawing a line to represent a single bond between each pair of bonded atoms.

• The first atom listed in the formula is usually the central atom.
• Also, remember that Hydrogen can only be bonded to one other atom.

Step Three: Find the number of valence electrons left over after forming the single bond.

• Remember, each single bond you draw counts for two electrons.

Step Four: Place electrons around the outside atoms until each is surrounded by eight electrons. (The octect rule)

• Hydrogen does not follow the octect rule, it will only have two electrons, Boron does not follow the octect rule as well, it will only need 6 electrons.

Step Five: Place any left over electrons around the central atom.

Here's an example of how a Lewis Structure looks for CO2

Kamila W.