Structure and Properties of Organic Molecule

8/9/2019 Structure and Properties of Organic Molecule

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Structure and Properties

of Organic MoleculeBy: Isman Kurniawan

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The orbital can be described by its wavefunction, which is the mathematical

description of the shape of the wave as itvibrates.

Wave Properties of

Electrons in Orbitals

Guitar string analogyfor 1s orbital.

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Wave Properties of


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Guitar string analogy for 2p

Wave Properties of


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Wave Properties of


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Molecular Orbital

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The hydrogen molecule; sigma bonding

The bonding that has most of its electrondensity centered along the lineconnecting the nuclei.

The 1s wave functions can addconstructivelyso that they reinforceeach other, the result is a bonding

molecular orbital.

Molecular Orbital

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Molecular Orbital

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The 1s wave functions can adddestructivelyso that they cancel out

where they overlap, the result is a

antibonding molecular orbital.

Molecular Orbital

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Molecular Orbital

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Relative energies of atomic and molecular

orbitals

Molecular Orbital

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Sigma overlap involving p orbitals

Overlap between two p orbitals

Molecular Orbital

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Sigma overlap involving p orbitals

Overlap between s orbital and p orbital

Molecular Orbital

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A pi bond results from overlap betweentwo p orbitals oriented prependicular to

the line connecting the nuclei.

Pi Bonding

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Pi Bonding

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Single and double bonds

A double bond requires the presence of

four electrons in the bonding region.

The first pair of electrons goes into thesigma bonding.

The second pair of electrons goes into api bonding.

Pi Bonding

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Single and double bonds

Pi Bonding

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Valence-shell electron-pair repulsion theory(VSEPR theory)

Hybridization and

Molecular Sha es

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sp hybrid orbitals

Hybridization and

Molecular Sha es

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sp hybrid orbitals

BeH2molecule

Hybridization and

Molecular Sha es

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sp2hybrid orbitals

Hybridization and

Molecular Sha es

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sp2hybrid orbitals

BH3molecule

Hybridization and

Molecular Sha es

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sp3hybrid orbitals

Hybridization and

Molecular Sha es

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sp3hybrid orbitals

CH4molecule

Hybridization and

Molecular Sha es

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Hybridization and

Molecular Sha es

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Shorthand notation to simplify 3D drawings

Drawing 3D Molecules

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Predict the hybridiziation, draw a picture ofthe 3D structure, and predict the bond

angles

1. NH3

2. C2H2

3. CH3CHO

Exercise

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Rotation of single bonds

Bond Rotation

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Rigidity of double bonds

Bond Rotation

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Rigidity of double bonds

Bond Rotation

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Bond dipole moments

Polarity of Bonds and

Molecules

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Molecular dipole moments


Molecules

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Molecular dipole moments


Molecules

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The effect of intermolecular forces

Melting points

Boiling points

Solubilities

Intermolecular Forces

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Dipole-dipole force


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The London dispersion force


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Hydrogen bonding

A hydrogen atom can participate inhydrogen bonding if it is bonded tooxygen, nitrogen, or flourine.


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Hydrogen bonding


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Rank the following compounds in orderof increasing boiling points. Explain the

reasons for your chosen order.

Exercise

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The general rule : like dissolves like Polar solute + polar solvent = dissolve

Polar solute + nonpolar solvent = doesnot dissolve

Nonpolar solute + nonpolar solvent =dissolve

Nonpolar solute + polar solvent = doesnot dissolve

Polarity Effects on

Solubilities

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1. For each of the following compounds,

a. Give the hybridization and approximate

bond angles around each atom excepthydrogen

b. Draw a 3D diagram, including any lone

pairs of electrons

NH2NH2& CH3COOH

Assignment

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2. Predict whether the compound will have a

large (>1D), small, or zero dipole moment.

Assignment

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Assignment

Submit in pdf file with appropriate format/layout

Deadline : 18 June 2014

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Quiz

Quiz 1 and 2

14 June 2014

Structure and Properties of Organic Molecule

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