Notes: Covalent Bonding
Ionic Bonds occur between atoms
with very different
electronegativities (metals and
nonmetals.)
If two atoms have similar
electronegativites, they share
electrons to comply with the octet
rule.
Two nonmetals form covalent
bonds.
Molecule: a neutral group of
atoms joined by covalent bonds.
Diatomic Molecule: molecule
made of only two atoms.
Diatomic Molecules
Hydrogen
Nitrogen
Fluorine
Oxygen
Iodine
Chlorine
Bromine
H2
N2
F2
O2
I2
Cl2
Br2
The word “Nitrogen” means both
the element and the molecule.
The substance nitrogen describes
the molecule N2.
Polar Bonds and Molecules
The type of bond formed between
two atoms depends on the
differences in their
electronegativities.
Electronegativity
Difference
Range
Most
Probable
Type of
Bond
Example
(Electronegativity
Difference)
0.0 – 0.4
Nonpolar
Covalent
H - H (0.0)
0.4 – 1.0
Polar
Covalent
H – Cl (0.9)
1.0 – 2.0
Very Polar H – F (1.9)
Covalent
> 2.0
Ionic
Na+Cl- (2.1)
Polar Molecules
If a molecule has a SYMMETRICAL
arrangement of polar bonds, it is a nonpolar
compound. EXAMPLE: CCl4
If a molecule has polar bonds and it is NOT
SYMMETRICAL, it is a polar compound.
EXAMPLE: HCl
VSEPR
Valence shell electron pair repulsion theory
explains and predicts the shapes of
molecules.
Since electrons are negative, they repel
each other and will occupy space as far
from each other as possible. (Two
electrons can occupy space together as a
pair because they’re spinning in opposite
directions.)
COORDINATE COVALENT BONDS
Coordinate covalent bonds are formed
when one atom contributes both bonding
electrons in a covalent bond.
The bonds behave just as other covalent
bonds.
EXAMPLE: Carbon monoxide