Hello. More information is needed to answer your question accurately. However, I will try to help you in the best possible way
If you are referring to what happens if the mass of an atom is greater compared to an atomic number, we can say that there is nothing too much, since it is normal for the atoms to have a mass slightly greater than the atomic number. The mass of an atom can never be less than the number of protons added to the number of neutrons. An atom with greater mass has a greater number of electrons and neutrons in relation to an atom of less mass and it is likely that the atom of less mass will donate or share electron with the atom of greater mass so that both reach the electric balance.