Summary EDEXCEL A LEVEL CHEMISTRY UNIT 3 REDOX I NOTES

3.1 OXIDATION & REDUCTION
24 January 2021
18:14
Oxidation is the loss of electrons.
Reduction is the gain of electrons.

Oxidising agents gain electrons and get reduced.
Reducing agents lose electrons and get oxidised.




3.2 EQUATIONS TO EXPLAIN OXIDATION AND
REDUCTION REACTIONS
24 January 2021
19:53
A redox reaction involves reduction and oxidation.

Metals usually form positive ions by loss of electrons, with an increase in oxidation
number.
● Positive oxidation number.
Non-metals usually form negative ions by gain of electrons, with a decrease in
oxidation number.
● Negative oxidation numbers.

A half equation is an ionic equation used to describe either the gain or loss of
electrons in a redox reaction.
Spectator ions - The ions don't change before and after the reaction, and don't take
part in the reaction.
Two half equations of different oxidising or reducing agents can be combined to give
the full ionic equation.

Displacement reactions are redox reactions used to compare relative strengths of
metals as reducing agents and non-metals as oxidising agents.