Sec 2 Formal Charges TABLE22 A Summary of Common Formal Charges Atom N 0 Structure Valence electrons Number of bonds Number of nonbonding electrons Formal charge 0 +1 Cengge Leaming.All Rights Reserv
Sec 2 Formal Charges
Sec 3 Resonance Resonance Forms Only electrons can be moved (usually lone pairs or pi electrons). Nuclei positions and bond angles remain the same. -The number of unpaired electrons remains the same. 离域 Resonance causes a delocalization of electrical charge. 共轭，共振
Sec 3 Resonance & Resonance Forms Only electrons can be moved (usually lone pairs or pi electrons). Nuclei positions and bond angles remain the same. The number of unpaired electrons remains the same. Resonance causes a delocalization of electrical charge. 共轭，共振 离域
Resonance Example 06: The real structure is a resonance hybrid All the bond lengths are the same. Each oxygen has a-1/3 electrical charge. 。… Has as many octets as possible. Has as many bonds as possible. Has the negative charge on the most electronegative atom. Has as little charge separation as possible
Resonance Example N O O O _ _ N O O O _ N O O O The real structure is a resonance hybrid. All the bond lengths are the same. Each oxygen has a -1/3 electrical charge. Has as many octets as possible. Has as many bonds as possible. Has the negative charge on the most electronegative atom. Has as little charge separation as possible
Solved Problem 2 Drawing Resonance Forms for an Anion Draw three resonance forms for the carbonate ion,CO32-. Carbonate ion
Draw three resonance forms for the carbonate ion, CO3 2- . Solved Problem 2 Drawing Resonance Forms for an Anion
Solved Problem 2 Drawing Resonance Forms of an Anion Strategy Look for one or more three-atom groupings that contain a multiple bond next to an atom with a p orbital.Then exchange the positions of the multiple bond and the electrons in the p orbital In the carbonate ion,each of the singly bonded oxygen atoms with its lone pairs and negative charge is next to the C=O double bond,giving the grouping O=C-O:
Strategy Look for one or more three-atom groupings that contain a multiple bond next to an atom with a p orbital. Then exchange the positions of the multiple bond and the electrons in the p orbital In the carbonate ion, each of the singly bonded oxygen atoms with its lone pairs and negative charge is next to the C=O double bond, giving the grouping O=C-O:- Solved Problem 2 Drawing Resonance Forms of an Anion