Chemical bonding -2Molecular geometry and hybridization of Atomic Orbital
10.1 Molecular Geometry
P. 411 - 420
Molecular
- Molecular Geometry is the three-dimensional arrangement
of atoms in a molecule.
Geometry
- Any molecule should be made up of two or more atoms.
- Molecule Example’s: CCl4, HCl, N2, ….
- Shape may be determined by VSEPR.
VSEPR
Planar triangular
Trigonal
bipyramidal
Tetrahedral
Octahedral
Valence
Shell
Electron
Pair
Repulsion
Essential
Question
How is VSEPR Theory used to
determine molecular
geometry?
Valence Shell Electron Pair
Repulsion Theory
What is
VSEPR
Theory?
Predicts molecular geometry
(shape)
Only works for:
 Covalent compounds &
polyatomic ions
 Compounds with central
atom
Steps to
Determine
Shape
1. Draw Lewis Dot Structure
2. Count # of lone pairs on
central atom
3. Count # of bonded atoms on
central atom
4. Determine shape using the
VSEPR Shape Chart
 The shape of a molecule can be categorized into 5
general shapes.
5 Types of
Shapes





1. Linear
2. Trigonal Planar
3. Tetrahedral
4. Trigonal Bipyramidal
5. Octahedral
 The geometrical shape is the arrangement of the
atoms around a central atom based on the number
of atoms, and the amount of lone pairs, which
contribute to the overall shape.
 AB2: BeCl2
Cl—Be–Cl
Bonding pairs repel each other, they must be at
opposite ends (To be as far as possible). The
predicted angle is to be 180 so the molecule is linear.
AB2
Molecules
Example: HgCl2, BeH2 and CO2.
 AB3: BF3
AB3
Molecules
Boron trifluoride has three bonding pairs repelling
each other as far as they can. The geometry is
Trigonal Planer, because all four atoms are in the
same plane, and the three end atoms form an
equilateral triangle.
 Examples: BH2, SO3, NO3.
B