1. 18th May 2012 Lewis diagrams and shapes of molecules
AIM – to revise drawing Lewis structures

2. Rules for drawing Lewis diagrams
Calculate the total number of valence electrons of all the atoms in the compound (care to account for ions)
Write the atom symbols in their approximate positions (put ion structures in square brackets with the charge on the outside)
Place one pair of electrons where there is a bond
Arrange electrons around the outer atoms first and then the central atom
Count the electrons around each atom. Shift electrons to make multiple bonds so that all atoms have a full outer shell of electrons and all valence electrons are paired.

4. Exceptions to the rules
Phosphate ion PO43-

5. Chlorate ion ClO4-

6. Quiz: (Movie) The Hunger games Who is the game maker of the 75th Hunger games?