State, in terms of the number of subatomic particles, one similarity and one difference between the atoms of these isotopes of element X.

The atomic number is determined by the number of protons in the atom.

Neutrons can vary the mass of atoms of the same element; atoms of the same element with the different atomic masses are called isotopes.

Electrons do not contribute a meaningful amount of mass to an atom, and only vary the charge of the atom. A charge atom is an ion.

Explanation:

i hope this is right :)

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link: