Compounds
REVIEW
Which Elements form Ionic Bonds?
• The central idea (for the 51st time) is that
electrons, one or more, are transferred
between the outer shells of adjacent
atoms. This creates Ions/Charged Atoms.
• Metals and NonMetals.
• Cation and anion.
• Certain Elements may donate or receive
more than one electron. It can therefore
bond with multiple elements, with different
ratios
History
• Before 1913, all bonds were considered to
be of the Ionic Type (called polar at the
time).
• When doing Ion Beam analysis for CO it
was found that the beam was evenly split
between Carbon and Oxygen.
• Early work was done by Thompson and
Rutherford.
Covalent Bonds
• The sharing of electrons in order to
achieve a more STABLE electron
structure.
• Atoms are held together closely by the
strong bond.
• Atoms that have similar electronegativity
values hold onto their electrons with the
same amount of force. They therefore do
not readily donate electrons.
Molecules
• The smallest amount of a covalent
compound that still has the properties of
that compound.
• The result of atoms held together by
covalent bonds.
• CO2
• SO4
Different Types of Covalent Bond
• Single Bond
– Two electrons shared between two atoms.
• Double Bond
– Four electrons shared between two atoms.
• Triple Bond
– Six shared electrons between two atoms.
Single Bonds
• Example: Halogens
– F2, Cl2, Br2, etc.
• Take place when 2 electrons are shared
between 2 atoms.
– Two atoms of the same element bonded to
Itself.
Double Bonds
• Four Electrons shared between two
atoms.
• Example: The Chalcogens
Triple Bonds
• Six electrons share between two atoms.
• Nitrogen is involved in many molecules
with a triple bond.
Covalent Bond Diagrams
Nitrogen
Hydrogen
Covalent Bond Diagrams
N
H
N
H
H
NH3
H
Diagram
e-e-
H
N
H
H
Practice Exercise #1
• Diagram the following Molecules and list
what type of bond they have:
– F2
- CO2
– Cl2
- H20
– O2
- N2
– SO
- NO
Naming Covalent Compounds
Naming Simple (Binary)
Covalent Compounds
Prefixes
1
mono-
6
hexa-
2
di-
7
hepta-
3
tri-
8
octa-
4
tetra-
9
nona-
5
penta-
10 deca-
Rules for naming
Covalent Compounds
• Name the 1st element by keeping its
elemental name.
Use a prefix only when there is more than one
of that element.
• Name the 2nd element as if it were
a negative ion. (ide)
Always use a prefix.
Watch awkward pronunciations
Tetraoxide
or
Tetroxide
Carbon Mono-oxide or Carbon Monoxide
Write the following formulas
nitrogen dioxide
tetraphosphorus
heptasulfide
carbon tetrachloride
tribromine octaoxide
Name the following compounds
C3O2
BrF3
P2O3
IF6