Respuesta :
Atoms of the same element are not necessarily identical. They might have the same atomic number (number of protons) but they will for sure have different number of neutrons, making their mass number different.
These are what we call isotopes.
For example take chlorine:
Cl-37
z=17 A=37
Cl-35
z=17 A=35
Answer: No, two atoms belonging to the same chemical element are not necessarily identical.
Explanation:
I hope that was helpful