Question

what happens at a synapse between two neurons

Answer 1

it secretes some Chemicals with electrical impulse and pass stimuli to next neuron

Answer 2

Synapse is a small gap between two neurons.
At the end of axon, a electrical impulse sets the release of some chemicals(acetylcholine) which cross the gap(synapse) and start a similar electrical impulse in the dendrite of the next neuron.