How do scientists determine the number of neutrons in an isotope of an atom a. they find the number of protons b. they add the number of electrons and protons c. they divide the atomic mass by two d. they subtract the atomic number from the atomic mass

An isotope of an element is having a different number of neutrons ex C12, C14...

In other words, they would have the same # of proton but different number of neutrons. So to determine the number of neutrons in an isotope of an atom, you need to subtract the atomic number from the atomic mass

For sure the answer is D

the correct answer is:

a. formation of precipitation