When protons or neutrons are added to an atom, the atomic number or mass may change, depending on which particles are added.
The atomic number of an atom is determined by the number of protons it contains. Adding protons to an atom increases its atomic number. For example, if you add one proton to an atom, the atomic number increases by one.
The mass number of an atom is the sum of its protons and neutrons. Adding protons or neutrons to an atom will change its mass number. If you add a proton, both the atomic number and the mass number increase. If you add a neutron, only the mass number increases, while the atomic number remains the same.
It's important to note that changing the number of protons in an atom will result in a different element altogether. The element of an atom is determined by its atomic number, so if you change the number of protons, you change the element. On the other hand, adding neutrons to an atom does not change its elemental identity, but it can affect its stability and create different isotopes of the same element.