1. Chemical Bonding Douglas J. Burks, Ph.D. Department of Biology Wilmington College of Ohio

2. Bonds and electrons All systems go to lowest energy state Lowest energy state is opposite charged particles as close to each other as possible Filled outer shell (s & p) lowest energy Take or share electrons to fill outer shell Periodic table organized by electron configuration

3. Bonds and Interactions NameBasis of Interaction Strength Covalent bond (polar) Sharing of electron pairs Strong Covalent bond (nonpolar) Sharing of electron pairs Ionic bond Transfer of electron with attraction of opposite charges Hydrogen bond Sharing of H atom with attraction of opposite charges of polar groups Hydrophobic Interaction Forcing of hydrophobic portions of molecules together in presence of polar substaces Van der Waals attraction Weak

4. Work Groups (4 students per group) A.Using both pictures and written text describe polar and nonpolar covalent bonds. A.how are they similar? B.How are they different? B.Why do we make such a big deal about there being two types of bonds A.How do they act towards other molecules.

5. Work Groups (4 students per group) Describe the hydrogen bond in pictures and written text. Why are hydrogen bonds weaker than ionic bonds? Why do we consider hydrogen bonds molecular interactions (not atomic interactions)?

6. Type of bond and how many Carbon and hydrogen Carbon and oxygen Carbon and 3 hydrdogens and fluorine

7. Discussion and Questions