• Today we will focus on the chemical bonds
between ions or atoms in chemical
compounds. We will review polar bonds from
chapter 2 and explore how they influence the
properties of a substance.
When your sneeze stalls for a second and
then suddenly comes booming out
• In Polar Covalent bonds the shared electrons
tend to be clustered closer to the strongly
electronegative atom than to the other atom.
• The electron “density” is greater around the
more electronegative atom.
Partial Positive The electron
density is less
Partial Negative The electron
density is greater
• A covalent bond’s polar nature depends on
the electronegativity difference between the
bonding atoms
Polar water molecules
are randomly distributed
Polar molecules in a liquid will orient
themselves so that their positive poles
are closer to the negatively charged strip
• Polar Molecule – a molecule in which the uneven
distribution of electrons results in a positive charge at one
end and a negative charge at the other end
• Non-polar Molecule – a molecule in which the electrons
are equally distributed among the atoms, resulting in no
localized charges.
General Chemical Formula
Polarity
Examples
Diatomic : 2 different atoms
Polar
HCl, CO
Nitrogen and 3 other atoms
of the same element
Polar
NH3, NF3
Oxygen and 2 other
elements of the same
element
Polar
H2O, OCl2
Carbon and other atoms of
two or more elements
Polar
CHCl3, C2H5OH
Diatomic: 2 identical atoms
Non-polar
N2, O2
Carbon and 2 or more
atoms of the same element
Non-Polar
CH4, CO2
1. Determine whether each of the following
molecules is polar or non-polar
a) Hydrogen bromide, HBr
b) Nitrogen gas, N2
c) Hydrogen sulfide, H2S
d) Ethane C2H6
e) Tetrachloroethene C2Cl4
f) Phosphine PH3