Answer
True.
Work Step by Step
Protons define the atomic mass of an element, and this determines the identity of the element. The number of neutrons can vary between atoms of an element, and each of the variations is an isotope. The number of electrons can also vary between atoms of the same element, and each of these variations is called an ion. However, if the number of protons varies between two atoms, these atoms are no longer identified as the same element.