The answer I believe would be C : tells you the identity of the atom because. The atomic number or proton number of a chemical element is the number of protons found in the nucleus.
Answer:
The solubility curve helps us to predict which substance will crystallize out first from a solution containing two or more solutes. The solubility curve helps us to compare the solubilities of different substances at the same temperature.
It tells you how many atoms it has, how many protons it contains and the number of electrons.