Molecular Structures

Trevor B., Savannah A., Michael H.

Structural Formulas /

Lewis StructureStructural Formulas are models using symbols of elements to show positions of atoms when bonded.

Lewis Structures show estimated models of the positions of both atoms and electrons in bonds.

What is the Structural formula of H2O?

What is the Lewis Structure of H2O?

Steps for drawing

Lewis Structures1: Predict The Location of the Atoms

2: Determine The Number Of Electrons Available

3: Determine The Number Of Electrons used in Bonding

4: Draw bonded pairs

5: Determine electron pairs remaining

6: Draw in remaining atoms and determine middle atom

Structural Formula/

Lewis StructureStructural Formula of

Water:

Lewis Structure of Water:

Types of Bonds

Single Bonds:

Double Bonds:

Triple Bonds

~Resonance~Resonance: Condition where molecules can be represented by more than one Lewis Structure

Examples: NO3 (Nitrate) and H3C2O (Acetate)

~Exceptions~Odd Number Of Valence Electrons: Not enough electrons to form full octets/bonds

Expanded Octet: More electrons than normal octet

Sub Octet: Less electrons than normal octet

Coordinate Covalent Bond: An atom donates 2 electrons to a hobo atom who needs them

Exception ModelsSub Octet:

Expanded Octet:

Coordinated:

Resources/Activities:

http://chemsite.lsrhs.net/bonding/images/lewis%20dot%20tutorial.swf

http://hyperphysics.phy-astr.gsu.edu/hbase/pertab/perlewis.html

Resource: Book