During resting condition, the concentration of K⁺ ions remains more inside the axoplasm while the concentration of Na⁺ ions remains more outside the axoplasm. As a result, the potassium ions moves from inside to outside because of the concentration gradient inside and outside the membrane. The K⁺  ions move faster as compared to sodium ions. Therefore, the membrane becomes positively charged outside and negatively charged inside. This is known as polarization of membrane or polarized nerve.