Transcript Bonding Day 4 Molecular Geometry Powerpoint

After today, you will be able to…
• Explain Valence Shell Electron Pair
Repulsion Theory (VSEPRT)
• Use structural formulas to describe
the molecular geometry of atoms
• Identify the correct geometric
name for the shape of the molecule
• Identify bond angles for molecules
Unit 4: Chemical Bonding
Molecular Geometry
Molecular Geometry
• Valence Shell Electron Pair
Repulsion Theory (VSEPR):The
electron pairs (both shared and
unshared) in the outermost energy
level try to get as far apart from
each other as possible.
– This determines the
shape of the molecule.
Shape: Linear
2 atoms
– Example: H2
H
H
~180˚
3 atoms
O C
O
– Example: CO2
Central atom must
have NO unshared pairs
Shape: Bent
3 atoms
– Example: H2O
H
O
H
~104.5˚
Central atom can have
one or two unshared
pairs of electrons
Shape: Trigional Planar
4 atoms
– Example: CH2O
O
H
C
~120˚
H
Central atom has
NO unshared pairs
Shape: Pyramid
4 atoms
– Example: NH3
H
~107.5˚
N
H
H
Central atom has
one unshared pair
Shape: Tetrahedral
5 atoms
– Example: CH4
H
~109.5˚
H
C
H
Central atom has
NO unshared pairs
H
Shape: Trigional Bipyramidal
• 6 atoms
– Example: PF5
F
F
F
~90˚
P
F
F
~120˚
For elements in period 3 and
higher, when bonded to Cl or F,
will have an expanded octet.
Central atom has
NO unshared pairs
Summary of Shapes
Linear
Bent
Trigional planar
Pyramid
Tetrahedral
Trigional bipyramidal