How do molecules activate pre synaptic neurons to activate? and also is it more the structure or the elements in the molecule that allows it to activate the neuron also how do molecules bind to receptors and same as last time what is more important to do so the elements in the molecule or the actual structure? please answer I cannot find the answer anywhere else expert answers are appreciated!

-Gus

neurons are activated or inhibited by neurotransmitters which bind to and act at specific cell surface receptors (which themselves are grouped into many very different classes includuing G-protein coupled receptors and ion channels).

Google or wikipedia are good places to start your research.