Question

The mass of the parts is always ___ the mass of the whole when looking at nuclear masses.

Answer 1

greater than

Step-by-step explanation:

When looking at nuclear masses, the mass of the parts is always greater than the mass of the whole.

Example with helium:

The atomic number of helium is 2, which means that it has two protons in its nucleus. The most common isotope of helium, ^4He, has two neutrons in addition to the two protons, giving it a mass number of 4. The mass of a proton is about 1.0073 atomic mass units (amu), and the mass of a neutron is about 1.0087 amu. Therefore, the total mass of the four nucleons (two protons and two neutrons) in the ^4He nucleus is:

2 protons x 1.0073 amu/proton + 2 neutrons x 1.0087 amu/neutron = 4.0314 amu

However, the actual (whole) mass of ^4He nucleus is found to be slightly less than the sum of the parts of the masses of its constituent nucleons. This means that the mass of the parts is always greater than the mass of the whole.

Answer 2

When looking at nuclear masses we speak of the processes nuclear fision and nuclear fusion. In fission a nucleus breaks up, into two nuclei. In fusion on the other hand two light nuclei combine to form one heavier nucleus. The relation
E=m*c^2. explains the difference in masses.
So, in case of nuclear fusion the mass of the parts is always more than the mass of the whole when looking at nuclear masses. In case of nuclear fusion. And in case of nuclear fision, the mass of the parts is always less than the mass of the whole when looking at nuclear masses. In case of nuclear fusion