Here is a PDF which will explain Redox reactions. The summary is below:
Oxidation-‐reduction (redox) reactions At different times, oxidation and reduction (redox) have had different, but complimentary, definitions.
Compare the following definitions:
Oxidation is: Reduction is:
•Gaining oxygen •Losing oxygen
•Losing hydrogen •Gaining hydrogen
•Losing electrons (+ charge increases) •Gaining electrons (+ charge decreases)