Final answer:
The Lewis structure for the neurotransmitter involves a positively charged nitrogen with three bonded hydrogen atoms and a lone pair, a carbon chain, and a negatively charged carboxylate group at the end. Each oxygen in the carboxylate has three lone pairs of electrons.
Step-by-step explanation:
The student is asked to draw the Lewis structure for a neurotransmitter molecule given by the structure ±NH3-CH2-CH2-CH2-C-O¹ with O having a double bond. The key features of this molecule will include a nitrogen atom with three bonded hydrogen atoms and a positive charge, a carboxylate group (COO¹) at the end with a negative charge, and a chain of carbon atoms (CH2) linking them. First, sketch out the carbon chain with the appropriate number of hydrogen atoms attached.
Begin with the positively charged nitrogen (±NH3) with three hydrogen atoms bonded to it and one lone pair of electrons to satisfy the octet rule. Use single bonds to connect the carbon atoms in the chain. Lastly, draw the carboxylate group at the end of the chain, with one carbon atom double-bonded to one oxygen atom and single-bonded to another oxygen atom, which carries the negative charge. Each oxygen atom should also have three lone pairs of electrons to fill their octet.
Remember that the nitrogen atom has four electron groups around it, three bonding pairs with hydrogen atoms, and one lone pair, which are directed to the corners of a tetrahedron to reduce repulsion.