When a neuron is not sending a signal, it is at rest.
At rest, the inside of the cell is negative relative to the outside.
Concentrations cannot balance; the cell membrane only allows some ions to pass through channels (ion channels).
A sodium-potassium pump (transport of ions that requires energy) creates an electrical potential along the neuron in which the cell is negatively charged and the environment is positively charged.
The resting membrane potential of a neuron is around
