Now note that electrons are not counted Naratomic mass because their mass is much smaller than that the proton or the neutron. Now the atomic number is the number of protons of our element. Now that number, the atomic number is the identity number of that element. It's used to identify our element. It's the fingerprint of that element. And that's because any element can have different number of electrons or neutrons but it will always have the same number of protons.