Section 1.3: Ions and Octet Rule
S CH 3 U
MS . F RA N K L IN
Valence Electrons
Valence electrons (VE) are the electrons in the outer shell of an atom. They determine how
reactive an atom will be.
The number of VE will help predict the following:
 number of bonds an atom will form
 the number of unpaired electrons
 an atom's formal charge.
Octet Rule
A full valence shell contains 8 electrons. When this occurs, the atom is considered to be stable,
also known as ‘stable octet’ or ‘full octet’.
Noble gases are considered to
have a stable octet.
The Formation of Ions
Atoms will gain or lose electrons in order to establish a stable octet. The number of valence
electrons determines their level of reactivity.
Cations: positive ions as a result of
losing an electron.
The Formation of Ions
Anions: Affects the atoms on the right side of the periodic table. Atoms will gain an electron to
have a stable octet. As a result, the atom becomes a negative ion.
Ionic Bonds and Nomenclature
During the formation of an ionic bond, atoms will transfer electrons to have a stable octet. The
anion’s name always follows the cation’s, and its suffix must be changed to –ide.
Cation
Anion
The Formation of Ions
Each group will indicate the
charge of the atom. Thus one
can predict how many
electrons that atom will lose or
gain when forming an ion.
Metals with Multiple Ionic Charges
Multivalent elements are elements that can form two or more different stable ions. Multivalent
elements are typically transitional metals which are found in the middle of the periodic table.
Nomenclature
Transitional metals will combine
with non-metals to form a stable
octet.
Metal
Ions
Classical
Names
IUPAC Names
Copper, Cu
Cu +
Cu 2+
cuprous
cupric
Copper (I)
Copper (II)
Iron, Fe
Fe 2+
Fe 3+
ferrous
Ferric
Iron (I)
Iron (III)
Manganese,
Mn
Mn 2+
Mn 3+
Mn 4+
N/A
Manganese (II)
Manganese (III)
Manganese (IV)
Polyatomic Ions
Polyatomic Ion: an ion, made up of more than one atom and acts as a single entity.
Polyatomic Ions
Hydrogen Carbonate – Blood pH
Calcium Phosphate – Bone formation
Ions in the Human Body
The human body requires a
balance of various ions to
ensure its proper functioning.
Homework
 pg. 22 of textbook: # 1, 3, 4, 6 - 8