Predicting Redox Reactions
To review:
Reducing agent:
a substance that loses electrons to another
substance in a redox reaction (e- giver)
Oxidizing agent:
a substance that gains electrons from another
substance in a redox reaction (e- taker)
 Whether or not electrons are transferred depends on which
substance has a stronger attraction to electrons
Redox Tables
 When comparing cations (positive metal ions), the most
reactive ions are the strongest oxidizing agents
 Example: Ag+ ion is more reactive than Cu2+ ion and therefore is
the stronger oxidizing agent (better e- taker)
 When comparing metals, the most reactive metals are the
strongest reducing agents

Example: Cu is more reactive that silver and therefore is the
stronger reducing agent (electron giver).
Copy Table 3 into your notes (pg 676)
NB: half reactions in redox tables are always written as reductions
Spontaneity
Redox spontaneity rule: a spontaneous redox reaction occurs only
if the OA is above the RA on a redox table. The more active
metal (stronger reducing agent) will stay/become an ion.
Example
Cu2+ + Zn
Cu + Zn2+ spontaneous (Zn becomes an ion)
Zn2+ + Cu
n.r.
nonspontaneous (Zn2+ stays an ion)