Complex sentence: In X-ray scattering, photons interact with the electronic cloud so bigger the element, bigger is the effect but in neutron scattering, neutrons interact with nuclei and interaction depends on isotope; some light elements like deuterium show similar scattering cross section as heavy elements like Pb.
Split into simpler sentences: In X-ray scattering, photons interact with the electronic cloud so the bigger the element, the bigger the effect is. In neutron scattering, neutrons interact with nuclei and the interaction depends on the isotope; some light elements like deuterium show similar scattering cross section as heavy elements like Pb.