Chemical Bonding

Douglas J. Burks, Ph.D.Department of BiologyWilmington College of Ohio

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

Bonds and InteractionsName Basis of

InteractionStrength

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

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.

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)?

Type of bond and how many• Carbon and hydrogen• Carbon and oxygen• Carbon and 3 hydrdogens and

fluorine

Discussion and Questions