1	Polar Covalent Bonds; Acids and Bases
2	What you should be able to do after this chapter. Identify bonds and molecules as polar, nonpolar or ionic. Draw Lewis structures and assign formal charges. Represent resonance structures. Define and use concepts of Brøsnted-Lowry and Lewis Acids and Bases to predict products. Tell where electron density is greatest and least. Draw Kekulé, condensed and skeletal structures.
3	Polar Covalent Bonds Are a consequence of electronegativity differences between atoms in bonds.
4	Electronegativity The measure of an atom’s ability to attract electrons it shares in bonds.
5	Bond Polarity Polarity is a separation of charge due to unequal sharing of electrons. The more electronegative element has a partial negative charge. The less electronegative element has a partial positive charge.
6	Bond Polarity
7	Charge Density in Polar Bond
8	This Leads to a Dipole Moment, m Polar molecules have a dipole moment.
9	Molecular Polarity Depends on presence of polar bonds And whether the dipole moments cancels Symmetry affects molecular polarity
10	A Nonpolar Molecule Can Have Polar Bonds
11	A Polar Molecule CH₃Cl₂
12	Formal Charge and Lewis Structures Smallest formal charge for atoms is preferred Most electronegative element gets negative formal charge. Least electronegative element gets positive formal charge.
13	Formal Charge and Lewis Structures Formal Charge =Group # - ½ Bonding e^-’s- Nonbonding e^-’s
14	Resonance: A Lowering of Energy Resonance will occur when 3 or more p-orbitals overlap to form a molecular orbital Resonance allows electrons to spread out over a larger region of space Resonance therefore leads to a lowering of energy Reactions leading to resonance are favored
15	Resonance: A Lowering of Energy 3 or more p-orbitals overlap.
16	Charge Density
17	Brønsted-Lowry Acids and Bases Acids donate a proton (H⁺) Bases accept a proton The strength of acids and bases is relative to their ability to lose or gain a proton Losing a proton creates a conjugate base Gaining a proton creates a conjugate acid
18	Brøsnted-Lowry Acids and Bases
19	Acid and Base: K_a [H⁺][A^-] K_a= [HA]
20	Acid and Base: pK_a pK_a= -log(K_a)
21	Relative Strength of Some Acids and Bases
22	Reactions of Acids and Bases Stronger acids react to form weaker conjugate bases Stronger bases react to form weaker conjugate acids
23	Electrostatic Potential Comparison of Conjugate Bases
24	Lewis Acids and Bases Bases donate electrons Acids accept electrons The strength of acids and bases is relative to their ability to gain or lose electrons Electron rich areas are bases Electron poor areas are acids
25	Lewis Acid-Base Reaction
26	A Lewis Acid-Base Reaction
27	Molecular Representations
28	What you should be able to do: Identify bonds and molecules as polar, nonpolar or ionic. Draw Lewis structures and assign formal charges. Represent resonance structures. Define and use concepts of Brøsnted-Lowry and Lewis Acids and Bases to predict products. Tell where electron density is greatest and least. Draw Kekulé, condensed and skeletal structures.