Aneutral atom and an ion of the same element have the same number of they have a different number of and hence reactivity.

a. Protons

b. Electrons

Explanation:

The atomic number of an element is also the proton number. Since the atom is neutral, the proton number and the electron number are equal. But this is different for an ion in that the element has either gain or loss an electron and so, the electron number differ from the proton number.