Molecular Geometry Notes

```R-13
Molecular Geometry Notes
VSEPR THEORY: _______________ _______________ between valence electrons
surrounding an atom causes these electron pairs to be located as far apart as possible.
V: _______________
S: _______________
E: _______________
P: _______________
R: _______________

VSEPR allows for the prediction of the ____________ _________ of molecules.

Geometric shape is based on _______________ and _______________ pairs of electrons
that are attached to the _______________ atom.

Unshared pairs are __________ the same as bonded pairs; unshared pairs push a little
harder!
Five Basic Shapes of Molecules:
1. ________________________________________
2. ________________________________________
3. ________________________________________
4. ________________________________________
5. ________________________________________

Five basic shapes of molecules:
Bond Angles
Central Atom
Examples
1) Tetrahedral
2) Trigonal pyramidal
3) Trigonal planar
4) Bent
a.
b.
5) Linear
a.
b.
c.
d.
e.
2
Hybridization

Valence electrons are found in _______________ and _______________

You would expect s to s bonds would be different than s to p bonds or p to p bonds, but
they are not. _________________________________________

Hybridization- the _______________ of two or more orbitals of similar energies on the
same atom to give __________orbitals of equal energy.

Orbitals blend to form special orbitals for bonding. Blended orbitals are _____________.

Hybridization explains how electrons can form identical bonds even though some are
from the ________________ and some are from the ________________.

___ ___ ___
p
___ ___ ___ ___
sp3 hybridization
______
s
Sigma and Pi Bonds

Single covalent bonds are also called _________________________.

Sigma bonds are formed when orbitals ______________ between the two sharing atoms
(hybrid orbitals.)

____________________ are the additional bonds that form from overlapping p orbitals.

They only form _______________a sigma bond is formed.

single bond – _______________

double bond – ____________________

triple bond – ____________________

The number of hybrid orbitals is determined by the
________________________________________________________________________
________________________________________________________________________

_________________________ indicates which orbitals are occupied
3
___ ___ ___
p
___ ___ ___ ___
sp3 hybridization
______
s
Shape
Generic Formula
# of sigma bonds
and unshared pairs
Hybridization
Tetrahedral
Trigonal Pyramidal
Trigonal Planar
Bent
Linear- when only two atoms, you must be told which one is considered the central atom
4
Polarity
 A polar molecule has _____ and _____ areas within it.
 Molecules _______ _______ be non-polar even if their bonds are polar: CO2.
 So how do you know?
________________________________________________________________________
 If uneven (not identical) distribution, then molecule is __________.
 If even distribution (identical), then molecule is __________.
 Look only at the _______________ _______________ when determining polarity of a
molecule.
 Unshared pairs are __________ the same as shared pairs.
Examples
____________________
____________________
____________________
5
Determining Polarity
After drawing the Lewis structure and identifying the molecular shape, it is easy to determine the
polarity of a molecule. After determining the shape, look at whether the atoms surrounding the
CENTRAL atom are all identical to one another. Bent and trigonal pyramidal molecules are ALWAYS
polar.
Molecular Shape
Linear
Bent
Trigonal planar
Trigonal pyramidal
Tetrahedral
Is everything surrounding
central atom identical?
Molecular Polarity
yes
non-polar
no
polar
-
polar
yes
non-polar
no
polar
-
polar
yes
non-polar
no
polar
6
```