Question

Why is mass defect negative?

Answer 1

It is also termed as 'missing mass' and represents the energy that was released when the nucleus was formed..

Explanation:

Since energy was released it means that it would be negative, recall on exothermic and endothermic reactions, when heat is loss, exothermic,the ethalpy becomes negative..

Mass defect is the equivalent to the binding energy, only negative, and it's negative because matter is lost, not gained, in small amounts, therefore energy is also lost `(E=mc²)` , not gained