Question

How does a change in mass arise when a nuclide forms from nucleons?

Short answer

The conversion of mass into binding energy to hold the nucleus causes a mass defect.

Step-by-step solution

To find how does change in mass arise

Mass defect is the decrease in mass when a nucleus forms from its nucleons. The decrease in mass is cause by the mass being converted into binding energy that holds nucleus together.

Hence Mass defect is caused by mass being converted into binding energy to hold the nucleus