Are there more sodium ions on the outside of cells or the inside?

At rest, there are more sodium ions on the outside of cells compared to the inside. This difference in sodium ion concentration is regulated by the sodium-potassium pump. The sodium-potassium pump is crucial for maintaining the resting membrane potential that is involved in essential processes such as propagating a neuronal action potential. The resting membrane potential of a neuron is approximately -70 mV. The sodium-potassium pump regulates the concentration gradient in a manner in which the interior of cells are low in sodium and high in potassium; K+ leaks from the inside of the cell to the outside, generating a negative charge on the inside of the membrane.