In the Structured Atom Model there is no strong nuclear force to hold the proton inside the
nucleus and there are no neutrons. Instead of neutrons we only have protons and what
are termed “inner electrons.” These inner electrons are the glue that holds the protons
in place binding them together into a nucleus. Let run through the principles that govern
this in SAM.
So what are the rules that govern the placement of these inner electrons? The natural position
would be between two protons, holding them together with the electrostatic force. This
inner electron needs at least 2 anchor points to be stable, generally this will be 2 protons.
Where there are multiple inner electrons they will attempt to place themselves as far away
from other inner electrons as possible. There is also another case to consider: that of
the neutron. In the SAM model there are no actual neutrons, instead these are protons
joined with an electron, a so called proton-electron-pairs. As there is no second anchor point when removed
from the nucleus this makes them unstable and we find in nature that “neutrons”
naturally decay into a proton and electron after about 15 minutes.
When we examine atoms in the periodic table we see that as we move along the table each
element has different properties that seem to be governed by the number of protons (and
their positions)but as we previously discussed these protons don’t always go up in steps
of one from one element to the next. In the SAM model an element is defined by the number
of proton-electron-proton constructs, in other words deuterons, which is a conglomerate of
a proton and a proton-electron pair.
In the following images we will denote the inner electron as a yellow sphere. These will
occupy the space between the protons. The actual shape and whether or not the inner
electron has a physical structure is not relevant at this stage.
If we examine helium we see 2 deuterons connected, Lithium 6 would be the next stable element
in the SAM model. We see 3 deuterons connected here. But this geometry leaves what is called
a neutron gap. We find heavier isotopes of Lithium. Lithium 7 is the most common form
of Lithium, and we can see it has an additional neutron or proton-electron pair on top of
the three deuterons. The additional inner electron this provides is not able to create
a new deuteron,therefore the properties remain as those of Lithium. If we add 2 additional
neutrons or proton-electron pairs we arrive at Lithium 9. We now have 3 proton-electron
pairs, so 3 additional inner electrons but again these have not formed a deuterons, so
it is still Lithium.
This is however an unstable nucleus and through the ejection of one of the inner electrons
in one of these proton-electron pairs via beta- decay the nucleus can rearrange the
internal electrons and form an additional deuteron creating the element Beryllium, which
contains four deuterons. This still has an additional neutron or proton electron pair
as a structure with 8 spheres is not stable as we discussed in the previous video. We
therefore end up going from Lithium 7 to Beryllium 9.
Adding another neutron or proton-electron pair we create Beryllium 10. This quickly
decays to Boron 10 through the ejection of an inner electron via beta- decay. This creates
yet another deuteron in the nucleus and therefore means it changes its properties from Beryllium
to Boron.
Adding two more proton-electron pairs creates Boron 12 which will decay through the emission
of an electron from one of the proton-electron pairs into Carbon 12.
In the previous episode we looked at the positioning of the protons up to carbon 12 using the densest
spherical packing method. The first elements mimic the buildup through the densest packing
principle exactly.
The important point to realise is that the number of deuterons plus the number of single
protons not bound in deuterons determines the element. The proton-electron pairs in
the nucleus which do not form deuteron pairs instead are responsible for creating the isotopes
of that particular element. This rule holds for the whole periodic table- with some small
modification. Addition of more neutrons or proton-electron pairs creates the isotopes
of an element.
The inner electron will also have a sphere of influence which stretches beyond a single
proton to the range of several protons. Current science will tell you that an electron is
a point particle with a point charge and no spatial extent. If however we consider what
is called the classical electron radius which is essentially a combination of fundamental
physical quantities that define the length scale for problems involving an electron interacting
with electromagnetic radiation then we find the electron seems to have a physical size
that is considerably larger than a proton.
These inner electrons are considered to be in fixed positions otherwise they would initiate
a nuclear reaction. The size of the electrons as well as their positions creates a sphere
that glues the protons in the solid shapes we looked at last episode. More inner electrons
will mean a stronger inward force.
If we take the example of Carbon 12 then this creates an icosahedron structure. The electrons
can be seen as the larger yellow spheres due to their increased range of influence. This
will create spots around this structure that will have a more positive charge compared
to others.
Could these areas play any role for the positioning of the outer electrons?
If we jump back to the deuteron, we can see this has two positive spots at the outer ends
of the protons while the inner electron sits in the middle. With deuterium there is only
one outer electron. This outer electron will be repelled by the inner electron and would
have to choose between one of the two poles. It would take a position that is as far as
possible away from the inner electrons and also as close as possible to the positive
nucleus hot spots.
Outer electrons follow the same rules as inner electrons and require 2 anchor points.
If we compare this to hydrogen 1 then it can easily be seen that there is no distinctive
positive spot meaning the outer electron could be anywhere around the proton.
One question you may ask is why does the electron not simply join with the proton to form a
proton-electron pair but as we stated there are not two binding points as there is only
one proton meaning it would not be stable. Creating a proton-electron pair even costs
energy.
As the nucleus structure gets larger these positive spots on the surface will determine
the locations of the outer electrons. The larger the structure the more likely the outer
electrons are more restricted in their movements.
If we take carbon as an example the outer electrons will arrange themselves around the
icosahedron with equal spacing.
So in simple terms the outer electrons arrange themselves in relation to the positive spots
on the nucleus while distancing themselves from one another due to repulsion from each
other. The system balances out the forces. An outer electron with more energy, ie. in
an excited state will be further from the nucleus, it may also be bigger. Since the
nucleus will continue to attract the outer electrons towards their original position
due to the densest packing rules, it will fall back to its ground state and emit the
energy it had absorbed.