What occurs in a half-cell? oxidation or reduction, but not both reduction only oxidation only?

Answer: In a half-cell is where occurs the either oxidation (loss of electrons) or reduction (gain of electrons) but not both.

Explanation:

1) In an electrolitic cell you can identify two half-cells.

2) In one half-cell occurs the oxidation

3) In the other half-cell occurs the reduction.

4) The half-cell where oxidation occurs is the anode.

In the anode the spieces increase its oxidation number, which is what oxidation means. Increasing the oxidation number means that the spieces is losing electrons.

5) The half-cell where reduction occurs is the cathode.

Reduction is the reduction of the oxidation number and this occurs due to the gain of electrons.