A student listed the characteristics of chemical and nuclear reactions. which of these statements best explains the identity of reaction d? it is a nuclear reaction because the atomic number remains the same when the number of valence electrons changes. it is a nuclear reaction because the atomic number remains the same when the particles are emitted from the nucleus. it is a chemical reaction because the atomic number remains the same when the number of neutrons and protons changes. it is a chemical reaction because the atomic number remains the same for all elements while a rearrangement of atoms through bonding occurs.