AP Chemistry – Class 52

Ascorbic Acid

Dates

Class Business

Big Idea: How do atoms arrange themselves in a compound?

Lewis Dot Structures

How To Construct Lewis Diagrams

Place the least electronegative atom in the central position (except hydrogen), surrounded by the remaining atoms
Calculate the total number of valence electrons available for the whole molecule or ion.
If the species under consideration is a polyatomic ion add or subtract as needed
Draw one line from the center atom to each of the outside atoms to symbolize a single bond.
Subtract two electrons for each bond from the total number of valence electrons.
Distribute the remaining electrons around their remaining atoms in such a manner as to best satisfy each atom
Electrons that are not involved in bonding should be shown as lone pairs by drawing a single dot for each electron.
At this point, identify if all of the atoms that are satisfied. (note: the octet rule only applies 100% for C/N/O/F)
If there are too few electrons to satisfy every atom, replace one single bond with a double bond on the unsatisfied atoms.
If your species is a polyatomic ion, put square brackets around your Lewis structure and place the overall charge of the ion on the outside of the square brackets.
If your compound is ionic, then take electrons from the metal and move them to the non-metal. Draw brackets around each separately, with the appropriate charge on each.

Practice

Homework

Chemteacher