1) The document discusses molecular geometry and polarity. It defines molecular geometry as the three-dimensional arrangement of atoms in a molecule. 2) Lewis electron dot structures are used to represent valence electrons around atoms. The octet rule states that atoms gain, share, or transfer electrons to achieve a stable 8 electron configuration. 3) Valence shell electron pair repulsion theory predicts molecular shapes based on the number of bonding pairs and lone pairs around a central atom. Symmetric shapes are nonpolar while asymmetric shapes are polar due to unequal electron sharing.

1. Polarity of
Molecules

2. • MOLECULAR GEOMETRY – another way to determine the
polarity of molecules ( polar of non – polar)

3. Molecular
Geometry
• Pertains to the three -
dimensional
arrangement of an
atoms in a molecule.

4. Lewis Electron Dot Structure (LEDS)
• The valence electron are represented using dot around the
symbol of the element.
OXYGEN
1
2
3
4
5
6
6 valence electron

5. O
The symbol of the element that represents the nucleus of the atom
O

6. F
Flourine
7 Valence electron
H
Hydrogen
1 Valence electron

7. H
Li
N
a
K
R
b
C
s
B
e
M
g
Ca
Sr
Ba
B
Al
Ga
METALLOI
D
NON-
METAL
META
L

9. WATER MOLECULE
Octet Rule: States that atoms tend to gain, share or transfer electron in
order to attain a stable 8 valence electron configuration
LONE PAIR
BONDING ELECTRON
H

10. Lewis Dot Structure of Water
H
H
BOND PAIRS
OXYGEN = 2 LONE PAIRS
HYDROGEN = 0 LONE PAIR

11. Lewis Dot Structure of Ammonia
N
H
H
H
NITROGEN = 1 LONE PAIR
HYDROGEN = 0 LONE PAIR
BONDING PAIRS?
3

12. To predict the shape of the
Molecule
Valence Shell Electron Pair Repulsion (VS
Theory
Key ideas of the VSEPR:
1. Electrons pairs stay as far apart from each other as possible to
minimize repulsions.
2. Molecular shape is determined by the number of bond pair and
lone pairs around the atom.
3. Treat multiple bonds as if they were single bonds. (in making
prediction)
4. Lone pairs occupy more volume than bond pairs

13. NOTE: Remember the arrangement of the specific number of electron pairs
and its corresponding VSEPR shape

22. Predicting the Shape of the Molecules
Count the number of
electron pairs around
the central atoms
1 2
3
4
4 Electron
pairs:
2 lone pairs
2 bond pairs

23. Predicting the Shape of the Molecules
Determine the
molecular geometry or
the VSEPR shape
BENT
2 Bond pairs
2 Lone pairs

24. Determining Polarity Using Molecular
Geometry
• Non – Polar molecule – if the shape of the
molecule is symmetrical.
equal sharing of electrons.
No dipole moment.
Valence electrons are shared equally on both
sides of an atom.

25. Example: Non Polar Molecules

26. CARBON DIOXIDE (CO2)
C O
O =
=
3.5 3.5
2.5
POLAR BOND
ELECTRONEGATIVITY

27. CARBON DIOXIDE (CO2)
C O
O =
=
3.5 3.5
2.5
POLAR BOND
ELECTRONEGATIVITY

28. Carbon Tetraflouride
C
F
F
F
F
TETRAHEDRAL
NONPOLAR

29. POLAR MOLECULE
•If the shape of the molecule is
asymmetrical.
Unequal sharing of electrons
between atoms.
Has dipole moment (partial positive
and negative)

30. EXAMPLE
Cl
H
Where Chlorine and Fluorine are more
electronegative than Hydrogen
H F
LINEAR SHAPE

31. BENT SHAPE TRIGONAL PYRAMIDAL