Two atoms of the same element cannot have different numbers of . a. particles c. protons
b. neutrons d. electrons.

c. protons

Explanation:

A "proton" is a subatomic particle that is stable and is positively-charged. You will identify the number of protons that is present in the nucleus of a chemical element by its "atomic number." It gives us an identity of the element, therefore, every atom of the same element have the "same" number of protons. For example, the number of protons for "Hydrogen" is 1. This means that even if you have two atoms of Hydrogen, each of them has "1" as the number of proton.