Chapter 10 bonding theory and molecular structure
Download
1 / 36

Chapter 10 Bonding Theory and Molecular Structure - PowerPoint PPT Presentation


  • 166 Views
  • Uploaded on

Chapter 10 Bonding Theory and Molecular Structure. Molecular Shapes The VSEPR model electron-pair geometries molecular geometries Molecular polarity Valence Bond Theory Covalent bonding and orbital overlap Hybrid orbitals sp hybrid orbitals sp 2 hybrid orbitals sp 3 hybrid orbitals

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Chapter 10 Bonding Theory and Molecular Structure' - faunus


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Chapter 10 bonding theory and molecular structure
Chapter 10 Bonding Theory and Molecular Structure


  • Molecular Shapes

    • The VSEPR model

      • electron-pair geometries

      • molecular geometries

    • Molecular polarity

  • Valence Bond Theory

    • Covalent bonding and orbital overlap

    • Hybrid orbitals

      • sp hybrid orbitals

      • sp2 hybrid orbitals

      • sp3 hybrid orbitals

      • hybridization involving d orbitals

    • Multiple bonds

      • double bonds

      • triple bonds

  • Molecular Orbital Theory

    • First-row diatomics

    • Second-row diatomics

  • Benzene and Aromatic Compounds


Valence Shell Electron Pair Repulsion Theory: regions of electron density

(single, double, or triple bonds or lone pairs) arrange themselves around an

atom to be as far apart as possible (electron pair repulsion).

Electron pair geometries:



Electron pair geometry: tetrahedral

Molecular geometry:

tetrahedral

trigonal pyramidal

bent


NI3 SO2

PCl4– NO3–

OF2 SO32–

BrCl3 PO43–


Molecular polarity  physical and chemical properties

d+d–

bonds: if DX > 0  polar bond A—B

molecules and ions: if dipoles do not exactly cancel, molecule will be polar

BeCl2 BF3 CH2O

CCl4 CHCl3 NH3

dipole


PCl3F2

CO32–

CHO2–


Bonds are formed using valence electrons and orbitals:

overlap

atomic orbitals molecular orbitals (covalent bonds)

e.g.,


But what about CH4?

Tetrahedral, all bonds

equivalent. How do we

get this from s and p a.o.s?


BeH2 facts:

2 equivalent bonds


BH3 facts:

trigonal planar,

3 equivalent bonds


tetrahedral,

4 equivalent bonds

CH4 facts:




Summary:

e– pair geometry hybridization

linear sp

trigonal planar sp2

tetrahedral sp3

trigonal bipyramidal sp3d

octahedral sp3d2


What is the hybridization of the central atom in each of the following?

CCl4 BrCl3

BF3 SF6

NH3 BeCl2

PCl4– XeF4


trigonal planar = sp2

all six atoms lie

in same plane

C2H4 facts:


C2H2 facts:

linear = sp


What is the hybridization of each indicated atom in the following

molecule? How many sigma and pi bonds are in the molecule?


Fact: O2 is paramagnetic!

Lewis structure

VSEPR

Valence bond theory

  • sp2 hybridized

  • lone pairs in sp2 hybrid orbitals

  • bonding pairs in s and p bonds

All show

all electrons

paired.


Overlap of wave functions:

constructive

overlap

destructive

overlap


Overlap of 1s orbitals:

s*1s

antibonding m.o.

(higher energy than

separate atoms)

s1s

bonding m.o.

(lower energy than

separate atoms)


(no. of e– in bonding m.o.s) - (no. of e– in antibonding m.o.s)

2

bond order =

H2

b.o. = 1 (i.e., lower energy than separate atoms)


He2

He2+

b.o. = 0

b.o. = 0.5


z

z

x

x

y

y

  • Molecular Orbital Theory

    • Second-row diatomics

Overlap of 2s and 2p orbitals

2s s2s and s*2s

(same as 1s),

then 2p orbitals give:

(i.e., 8 a.o.s  8 m.o.s)


E




benzene

C6H6

6 e– in a cyclic,

planar p system

 aromatic stabilization

all sp2

120º

  • Benzene and Aromatic Compounds

planar

hexagon


naphthalene

benzo[a]pyrene

(carcinogen)

p-dichlorobenzene

  • Benzene and Aromatic Compounds

methylbenzene

toluene

1,2-dimethylbenzene

ortho-dimethylbenzene

(o-xylene)

(meta-xylene)

(para-xylene)


ad