Final answer:
The chief cations in intracellular fluid are potassium and magnesium. Sodium is the principal ion in the fluid outside of cells.
Step-by-step explanation:
Intracellular fluid: Chief cations of intracellular fluid are potassium and magnesium. Less amount of Na is present. Calcium content although very little, but is biologically very important. Contains much more phosphate and sulphate ions as well as proteins than the extracellular fluid. Chloride ion is practically absent in intracellular fluid except in case of erythrocytes.
Extracellular fluid: All cells of the body exist in fluid environment collectively called as extracellular fluid. This includes blood plasma, interstitial fluid and lymph. Plasma contains 7% protein, hepatic lymph slightly less and subcutaneous fluid 1%. They contain mainly NaCl, NaHCO3, small amount of Ca, Mg, K, H, phosphate, sulphate, organic acids, non-electrolytes such as glucose, urea, lipids etc. pH value ranges from 7.35 to 7.45 under normal conditions.
Sodium is the principal ion in the fluid outside of cells. Normal sodium concentrations are about 10 times higher outside than inside of cells.