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Transcript of Nucleus
The nucleus is the heart of the atom. It is the location of all the positive charge and of nearly all the mass. Yet is is very small compared to the size of the atom. Let us first list some terms.
A = atomic mass number - designates isotopes and is equal to the number of protons plus neutrons: A = Z+N
N = number of neutrons - causes isotopes
Z = number of protons - designates the element
(here X is the abbreviation for any element: C for carbon)
Radius of the nuleus is
The mass density is m/V. mass is proportional to A, and Volume is proportional to A, so for any element the density is thus approximately the same.
The mass of the nucleons are so small that we often don't write them in terms of kilograms, rather we have defined the unified atomic mass unit (u)
From Einstein we learn that energy is equivalent to mass, so we can also write this mass as an energy.
Thus for example here are a few values.
Putting these concepts together we can compare masses or elements and masses of their components.
And we find that the masses don't Equal!
If the mass of the element is always smaller than the mass of its parts. The amount of mass difference can be thought of as the 'energy' required to bond the nucleus together, which we call the bonding energy. We find it by taking:
We can also find the amount of binding energy for each individual nucleon, as:
How many protons and neutrons are in Cd
cadmium is element 48 and
Z = 48
N = 66
N = A - Z = 114 - 48 = 66
How big is the nucleus?
What is the bonding energy per nucleon?
= 972.6 MeV