Control of Structure

Why do elements and compounds adopt one structure as opposed to

another?

Thermodynamics Review:

G = H - TS

Bond Strength

Favored by strong bonds.

Freedom of Movement

Favored by more particles.

Temperature Control?

Thermodynamics Review:

G = H - TS

Bond Strength

Favored by strong bonds.

Freedom of Movement

Favored by more particles.

Example: Cl-Cl vs. Cl Cl

Cl-Cl bond strength = 242 kJ/molSo (Cl) = 165 J/KmolSo (Cl2) = 223 J/Kmol

Bonding Concerns and Trends:

Number of bondsType of bonds: sigma vs. pi

Number of Bonds Possible: F, O

Number of Bonds Possible: N, C

Lewis Base Activity Expands # Bonds

sigma vs. pi bonding: Lewis structure examples

Shapes of sigma and pi bonds

sigma vs. pi bonding: shapes, strength and trends