Answer
Potassium(K+) has a higher concentration -- approximately 150 mM)-- in the cytosol than it has in the extracelullar fluid--approximately 5 mM.
Work Step by Step
In the extracellular fluid (ECF), the concentration of potassium[K+] is low --approximately 5mM, but in the cytosol its concentration is much higher --approximately 150 mM. On the other hand, sodium concentration [N+] is higher extracellularly--approximately 150 mM , but lower intracellularly--approximately 15 mM-- than potassium.
