At a synapse, the electrical impulse travelling along the axon of one neuron triggers the release of chemicals at the axon's end. These chemicals cross the gap (synapse) and generate a similar electrical impulse in the dendrite of the next neuron, thus transmitting the signal from one neuron to another.
Examiners look for two key steps: (1) conversion of electrical impulse → chemical release at axon end, and (2) chemicals crossing the gap → new electrical impulse in next neuron's dendrite. Both steps are needed for full 2 marks. Avoid just saying "signals are passed" — specify the electrical-to-chemical-to-electrical sequence.
Source: Chapter 6, Section 6.1 Animals – Nervous System