Final answer:
The nurse determines that the client's potassium level is normal if the value noted is between 3.5 and 5.0 mEq/L.
Step-by-step explanation:
The nurse determines that the client's potassium level is normal if the value noted is between 3.5 mEq/L and 5.0 mEq/L. According to the information provided, the normal range for serum potassium is 14-20 mg/100 ml. Since 14-20 mg/100 ml is equivalent to 3.5-5.0 mEq/L, any value within this range would be considered normal.