The chemistry
A cathode is the negative electrode in electrolysis; the anode is positive. Positive ions move towards the cathode and negative ions towards the anode.
An electrolyte conducts electricity because its ions can move. Molten means melted; aqueous means dissolved in water. A binary compound contains two elements. When a binary ionic compound is molten, its own ions take part. In an aqueous solution, ions from water can also take part.
Electrode material also matters. A copper anode in copper sulfate can dissolve; an inert graphite anode cannot supply copper ions. Inert means it does not react under the stated conditions. Use the electrolyte and electrodes named in each question.
Higher questions also ask you to write half-equations. Both atoms and total charge must balance. Check that both the atoms and the total charge balance, even when you have the right products.
Worked example
Aqueous copper sulfate with inert graphite electrodes gives copper at the cathode and oxygen at the anode.
In the copper-electrode variant, the cathode gains copper while the anode loses copper. This active-electrode scenario is enabled for the Edexcel profile here.
Specification references
AQA 4.4.3; Pearson 3.23–3.31. Copper-electrode practical variant: Pearson appendix printed p60; The copper-electrode variant appears only for Edexcel.