What is the junction between the axon of one neuron and the dendrite of another neuron called?

Axon terminal is indicated by which alphabet in the given figure?

What is the functional junction between two neurons called?

True about electrical synapses:
$(I)$. Pre and postsynaptic neurons are in very close proximity.
$(II)$. Pre and postsynaptic neurons are separated by a synaptic cleft.
$(III)$. Impulse transmission is very fast.
$(IV)$. Electrical synapses are common in our system.
Select the correct option.

Explain:
$(1)$ Electrical Synapse
$(2)$ Chemical Synapse

The chemical causing the transmission of nerve impulse across synapses is