1. REVISION
ELECTROCHEMISTRY

2. REDUCTION CATHODE Reduction is a gain of electrons
The oxidation number decreases
E.g.
Electrodes where reduction take place will increase in mass
We write the reduction reaction ‘right-way-round’ from the table
Oxidising agent
CATHODE
The electrode where reduction takes place

3. OXIDATION ANODE Oxidation is a loss of electrons
The oxidation number increases
E.g.
Electrodes where oxidation take place will reduce in mass
We write the oxidation reaction ‘upside-down’ from the table
Reducing agent
ANODE
The electrode where oxidation takes place

4. ELECTROLYTE
solution/liquid/dissolved substance that conducts electricity through the movement of ions.

5. OXIDATION NUMBERS (p23) OXIDATION RULES fluorine is always -1
The rest of the halogens chlorine, bromine and iodine usually -1,
unless they bind with oxygen or fluorine - then we will have to work out their oxidation numbers
Hydrogen is usually +1
unless it binds with a metal, then it is -1
OXYGEN is usually -2,
except it is -1 in H2O2 and O22- and
+1 if it binds with fluorine
Group 1 is always +1
Group 2 is always +2
The most electronegative element always has the negative oxidation number
Neutral diatomic molecules such as H2 and Cl2's oxidation number is 0
Isolated ions’ oxidation number is equal to the charge according to the periodic table
OXIDATION NUMBERS (p23)