Bonding Thermodynamics: why reactions occur Kinetics: how reactions occur Organic chemistry: chemistry of carbon chemistry of life Bonding Lewis dot structures: valence e- used in bonding # valence e- = group # “noble gas” = 8 valence e-

Lewis structures CH3OH 1. Determine # valence e- element group number e- C IV 4 H I 1 O VI 6 2. Place least electronegative element in center (never H)

non-polar covalent  0.4 polar covalent 0.5-1.8 NaCl = 3.0 - 0.9 = 2.1 ionic Cl-Cl = 3.0 - 3.0 = 0.0 covalent C-O = 3.5 - 2.5 = 1.0 polar covalent C-H = 2.5 - 2.1 = 0.4 covalent

Lewis structures 1. Determine # valence e- 2. Place least electronegative element in center (never H) C 3. Make single bond (2e-) between each pair of atoms 4. Use remaining e- to satisfy octet rule 5. Use double or triple bonds to reduce # of unshared e-

Lewis structures : : : : : : : CH3OH C H O valence e- 4 4 6 14 e- H H

Lewis structures formal charge COCl2 C O Cl valence e- 4 6 14 24 e- .. 7 - 4 - 2 = +1 .. .. .. .. O .. .. 6 - 6 - 1 = -1 .. C O Cl 7 - 6 - 1 = 0 .. 6 - 4 - 2 = 0 group number - unshared e- - (1/2) shared e-

Resonance Lewis structures move e- atoms stay the same -1 -1 +1 +1 Lewis structures move e- atoms stay the same contributing structures + on electronegative element carbonate, CO32- 3 equivalent contributing structures lowers the P.E. of carbonate makes CO32- more stable

VSEPR Molecular geometries : H2O : : H O H : 4 - : H2O : : H O H + + : 4 pairs of valence e- on O tetrahedron bonds angles 109.5o actually 108o polar bonds dipole moment H-bonding H bound to O, N, F = H-bond donor O, .. N, .. .. F = H-bond acceptor

VSEPR Molecular geometries : CH2O : : H C H : : : O : 3 + : CH2O : : H C H : : : O : - 3 pairs of e- on C trigonal planar bonds angles 120o

VSEPR Molecular geometries : : CO2 : : : : : : O C O : : + : CO2 : : : : : : O C O : : - - 2 bonding pairs of e- on C linear bonds angles 180o

: H2O : : H O H : O ___ s electrons ___ p electrons 2 4 equivalent orbitals 4 Hybridization atomic orbitals s p s p 3 -bond molecular orbitals

H : C : H CH2O : : : : O C ___ s electrons ___ p electrons 2 3 equivalent orbitals 2 Hybridization atomic orbitals s p p -bond sp2 -bond molecular orbitals

H : C : H CH2O : : : : O O ___ s electrons ___ p electrons 2 3 equivalent orbitals 4 Hybridization atomic orbitals s p p -bond sp2 -bond molecular orbitals

: : CO2 : : : : O C O : : C ___ s electrons ___ p electrons 2 2 equivalent orbitals 2 Hybridization atomic orbitals s p p -bond sp -bond molecular orbitals

: : CO2 : : : : O C O : : O ___ s electrons ___ p electrons 2 3 equivalent orbitals 4 Hybridization atomic orbitals s p p -bond sp2 -bond molecular orbitals