When an axon is at rest, the concentration of ions on either side of the membrane are different. Which of the following is correct about the concentrations ions on either side of the membrane?

A. There is an excess of potassium ions inside the axon and an excess of sodium ions outside
B. The inside of the axon becomes positively charged while the outside is negatively charged
C. There is an excess of sodium ions on the inner side of the axon
D. Chloride and potassium ions begin to move across the membrane
E. Calcium ions accumulate on the inner side of the axon

Correct Answer:

Option A – There is an excess of potassium ions inside the axon and an excess of sodium ions outside