Success 24/7 Chemistry: Valence Electrons and Charges Notes
Valence Electrons: Electrons on the outermost energy level of an atom. These electrons are involved in
bonding.
You can predict the number of valence electrons each of the representative elements (Group A
elements) have based on their location on the periodic table.
How many valence electrons do atoms of the following elements have?
Element
Symbol
# of Valence
Electrons
Mg
Br
C
Al
Ne
Lewis Dot Structures
Used to represent the number of valence electrons in an element or compound.
Na
Ex:
Element
Symbol
# of Valence
Electrons
Lewis Dot
Structure
Mg
Br
C
Al
Ne
2
7
4
3
8
Octet Rule:
Atoms will gain, lose, or share electrons in order to become stable like a noble gas. Most noble gases
have 8 valence electrons (except for He, which is stable with only 2).
If the atoms gain/lose electrons, an ion with a charge will be formed. Groups tend to have the same
number of valence electrons, so they will also tend to have the same charge.
In general, metals lose electrons and become positive ions (cations).
In general, nonmetals gain electrons and become negative ions (anions).
(Remember, electrons are NEGATIVELY charged. If an atom loses electrons, it now has more
protons than electrons making it positive.)
Element
Symbol
Atom’s Lewis
Dot Structure
Ion
Symbol
Ion’s Lewis
Dot Structure
Na
P
O
Ca
F