Question

what must differ between the atom of two different elements?
o electrons in the atom
o protons in the atom
o neutrons in the atom
o protons and neutrons in the nucleus

Explanation:

The identity of an element is determined by the number of protons in its atom's nucleus. Different elements have different numbers of protons. Electrons can vary in ions, and neutrons can vary in isotopes.

Answer:

protons in the atom