examine the locaiton of sodium ions in model 2 is sodium more concentrated on the inside or outside of the cell membrane.

Model 2 is not provided in the question. In the nervous system, the sodium-potassium pump maintain a membrane potential across the plasma membrane, with the inside of the cell negative and the outside positive. This is called resting potential, and in this case Sodium is more concentrated in the outside of the cell and Potassium is more concentrated in the inside of the cell.

Explanation:

Neurons are the cells of the nervous system that are excitable, with the capacity of generate and transmit electrical signals known as nerve impulses or action potentials. Neurons have an extension called axon that allow to conduct the action long distances.

During the resting potential, the antiporter enzyme called sodium-potassium pump expels sodium outside the cell exchanging them for potassium using ATP.

An action potential is generated when an stimulus opens ion channels that permit the income of Sodium, changing the voltage in the inside of the cell and opening more voltage-gated Na and K channels. In this process, a flow of electric current is transmitted along the axon of the neuron.