10/25/2016
Review: Metal vs Nonmetals
Review: Ionic vs Covalent Bonding
C. Eugene Bennett Department of Chemistry
Ionic compounds are brittle and crack
C. Eugene Bennett Department of Chemistry
Lewis symbols for elements
Unpaired dots = bonding capacity
• main group elements ⇒ #
valence e-s = group #
– same group ⇒ same
valence ⇒ similar
properties
C. Eugene Bennett Department of Chemistry
Resonance
C. Eugene Bennett Department of Chemistry
Resonance in benzene, C6H6
Occurs when two or more equivalent Lewis structures can be
drawn for one compound
• the same arrangement of
atoms but different
arrangement electron pairs
C. Eugene Bennett Department of Chemistry
C. Eugene Bennett Department of Chemistry
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10/25/2016
Estimating ∆Hrxn
Bond Types
break ‘em all– make ‘em all
CH4 + 2O2 → CO2 + H2O
Cl2: Pure covalent
C. Eugene Bennett Department of Chemistry
HCl: Polar covalent
NaCl: Ionic
C. Eugene Bennett Department of Chemistry
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