Astudent writes the following statements about the relationship between mass defect and nuclear binding energy. 1. when an isotope’s protons and neutrons come together to form a nuclide, a small amount of mass is converted to energy. 2. an equivalent amount of energy must be added to the nuclide to split apart its protons and neutrons. 3. statement 1 describes the isotope’s nuclear binding energy, and statement 2 describes the isotope’s mass defect.

Answer is: 1 and 2 only statements are correct.

The missing mass of a nucleus is called its binding energy, the energy needed to break it up into separate protons and neutrons.

Average binding energy per nucleon equals total binding energy divided by mass number (sum of protons and neutrons in an atom).

Mass defect is the difference between the mass of a composite particle and the sum of the masses of its parts.

The mass defect can be explained using Albert Einstein's formula E = mc².