Covalent Bonding Part 3: Hybridization, Bond Geometry and Resonance Structures

Orbital Hybridization Looking at the aufbau chart for carbon, how many unpaired electrons do you see? How many bonds should this lead us to believe carbon will form? S P

sp3 We know that carbon will form 4 bonds The Lewis Dot structure for carbon shows us this When we look at the orbitals for carbon, we will see that the s and p orbitals combine into one sublevel with 4 hybrid orbitals called sp3 orbitals This model of hybridization explains why carbon will form 4 bonds sp3 S P

Bond Geometry The hybridization of orbitals leads to predictible geometric shapes for molecules. You need to memorize the following geometric shapes of molecules:

Resonance Structures Resonance structures occur when there are 2 or more equally correct Lewis dot structures for a molecule The actual molecule is a blend or intermediate of the possible resonance structures Example: Ozone (O3) Draw the possible resonance structures for NO2

Resonance Structures Draw the possible resonance structures for NO2

Coordinate Covalent Bonds A coordinate covalent bond is when one atom in a bond contributes both electrons to make the bond Consider CO Oxygen is now happy and meets the octet rule What about Carbon? C O

Coordinate Covalent Bonds Oxygen will contribute 2 electrons to form a third bond, allowing carbon to meet the octet rule C O C O