Draw the following lewis structures in your
notes: (we will use these as examples for
today’s discussion)
1. H2
2. CH4
3. CO2
4. H2O
5. CH2O
6. CHF3
Electronegativity
● DEF: Ability of an atom to attract electrons in a
chemical bond
● More EN atoms are going to want e- more
badly.
● Higher EN = Stronger Pull of e○ Not Strong Enough to rip e- away (ionic)
Common Trends in Polarity
● Any bond between two same atoms (ex H-H) is
considered to be nonpolar.
● Any C-H bond is considered to be nonpolar.
● Any bond between two atoms of different species
is considered to be polar.
○ The further they are from each other on the
PT, the more polar the bond (more different in
EN)
Polarity in Molecules
Equal Sharing vs. Unequal Sharing
Polarity & Electronegativity
● Polarity is a term used to describe the sharing of
e- within a bond.
● The term ‘polar’ is applied when there is
unequal sharing of e● Difference in EN can be found to identify
polar/nonpolar bond.
○ Nonpolar means sharing is nearly =
Visual Representation of Polar Bonding
2 Methods to Show Polarity in Bond:
1) Partial Charges
2) Vector Diagram
Points from Less EN to More EN where e- will
be pulled
More EN atom will receive
partial - sign. Electrons will be
pulled closer to it.
Molecular Polarity
A mo
lecula
over
r ca
a
conta ll nonpo n be
● Individual bonds can be described as
lar b
in po
ut
lar b
onds
polar/nonpolar/ionic.
!!!
● The same can be applied an overall molecule.
● Nonpolar molecule:
○ 100% Symmetrical
○ No Lone Pairs on Central Atom
○ Polar Bonds Pulling Opposite Directions
Molecular Polarity
● A polar molecule will:
○ Contain polar bonds
○ Have a lone pair on central atom
○ Peripheral atoms of different types