November 7th Notes

Pairing Lewis Structures with Many Atoms
1) Gather information

• Draw a Lewis structure for each atom in the compound. When placing valence electrons around an atom, place one electron on each side before pairing ant electrons on each side before pairing an electrons
• Determine the total number of valence electrons in the compound

2)Arrange Atoms

• Arrange the Lewis structure to show how the atoms bond in the molecule
• Halogen and Hydrogen atoms often bond only to one other atom and are usually at the end of the molecule
• Carbon is often placed in the center of the molecule
• You will find that, with the exception of carbon, the atom with the lowest electronegative is often the central atom

3) Distribute the dots

• Distribute the dots so that each atom is satisfied (With exception of Beryllium, Boron, and hydrogen).

4)Draw bonds

• Change each pair of dots that represent a shared pair of electrons by a large dash

5) Verify Structure

• Count the number of electrons surrounding each atom. Except for hydrogen, beryllium, and boron all atoms most satisfy octet rule. Check that the numbers of valence electrons is still the same number you determined in Step 1.

Here is a site that has many of sample problems that you can practice with

http://www.colby.edu/chemistry/webmo/mointro.html