{Year 2} Chapter 12 - Nuclear Energy (Just done pg 213)

Question 1

What is mass defect and why does it exist?

Answer 1

The difference in mass between an atom and the sum of the masses of the protons, neutrons, and electrons of the atom. It is a result of the binding energies holding the atom together where some of the masses of the separate components have been taken to formulate the strong nuclear force and keep the atom together

Question 2

What is the relationship between binding energy and mass defect in equation form?

Answer 2

Binding energy = mass defect x c^2

Question 3

What is the definition of an atom mass unit?

Answer 3

1/12 of the mass of Carbon-12, or 1.661 x 10^-27kg. In energy form, it is also equivalent to 931.5 MeV

Question 4

Is a higher or lower binding energy energy per nucleon more stable?

Answer 4

Higher - a proton has the highest binding energy per nucleon and is thus the most stable known nucleus

Question 5

Why is a high binding energy per nucleon more stable?

Answer 5

As it takes more energy to pull the nucleons apart with a higher binding energy

Question 6

Describe the graph of nucleon number against binding energy per nucleon?

Answer 6

The binding energy per nucleon increases rapidly for the lighter elements // Helium nuclei are very stable relative to other low mass nuclei - which is why alpha emission is more common that proton emission // Binding energy per nucleon is at its peak for Fe-56, and decreases with increasing nucleon number for stable nuclei after Fe-56