G'day love! An elements atomic number is the amount of protons in an element!
Answer:
The answer is "3.81041978"
Explanation:


In 1860 





There are a couple of ways in which you can express the concentration of a solution, and here they are: gram per liter (g/L), molarity (M), parts per million (ppm.), and percents (%).
As you can see, only M appears in your answers, which means that the correct option should be (2) 3.5 M.