“Happy” Elements
 All elements want to
be “happy”
 An atom wants a
stable outer energy
level to make them
“happy”
How do they become happy?
 Atoms will gain or lose
electrons in order to
become stable.
 Usually the most stable
configuration involves
having 8 valence e 8 electrons = full octet
Stable Elements…
 Nobel Gases do not need to transfer or
share any electrons because they already
have 8 valence electrons and are stable
Octet Rule
 Atoms will form bonds with other atoms
in order to have eight valence electrons.
 Can share or transfer electrons with other
elements
 Elements will not just lose or gain electrons. They
will give to another element or take from another
element
Oxidation Numbers
 The oxidation
number indicates
how many
electrons are going
to be lost or gained
during bonding.
 Range from -4 to +4
Predicting Oxidation Numbers
1. First, determine how many valence electrons
the neutral atom has.
2. Determine if the atom will lose or gain
electrons.
 Ask yourself, which would be faster?
A) Losing down to zero
 B) Gaining up to eight

3.Count the number of electrons gained or lost.
If you lose electrons, the charge will be (+)
If you gain extra electrons, the charge will be (-)
Practice
 What would the oxidation number be for the following
atoms?
 A) Lithium
1+
B) Sulfur
2-
 C) Aluminum
3+
D) Iodine
1-
 E) Phosphorous 3 G) Neon
0
F) Carbon 4±
Oxidation #s on the PT