During nuclear decay, a new isotope is created. how is the nucleus of the new isotope different from the parent if the parent isotope has undergone beta decay? a) the atomic number increases by 4 and the mass increases by 2. b) the atomic number increases by 2 and the mass decreases by 4. c) the atomic number increases by 1 and the mass remains the same. d) the atomic number remains the same and the mass decreases by 1.