Chemical Bonding

Chapter 6

Molecular Geometry

VSEPR

Valence – Shell, Electron Pair Repulsion

Theory

VSEPR

• How a molecule “looks” in real space (3D).• Based upon electron domains (where electrons

are)– Bonds are domains (doubles/triples count as one)– Unshared electron pairs are domains– Electron domains repel each other– Unshared pairs repel more than bonding pairs– Domains orient themselves as far away from each

other as possible.

• Development of bond anglesVisual Concepts

• Electron domains or concentration of electrons repel each other to form shape

• Lone pair geometryVisual Concepts

Vsepr.mov

Memorize!

• Shapes and angles– Linear 180o

– Trigonal planar 120o

– Tetrahedral 109.5o

– Trigonal pyramidal 107.5– Bent 104.5– Trigonal bipyramidal 90o 120o

– Octahedral 90o

Guess the shape!

Hybridization• When atoms come together in a covalent bond,

they overlap orbitals of differing energy creating orbitals of equal energy.

Intermolecular Forces

Polar Molecule • One end negative, one end positive

Dipole• Molecule that has two poles

Different types of intermolecular forces

• Induced dipole• Hydrogen bonding• London dispersion

• Visual Concepts- Induced dipole

• Visual Concepts- London dispersion

Hydrogen Bonding.MOV