Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: Nicholas Lee on 29/05/2016 21:22:25
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Do all electrons reside in the ground state, when the band gap is increased, or decreased, as atoms come together to form molecules.?
Like in glass, transparent liquids, and plastics.
As atoms come together to form glass, like silicon, sodium, and calcium.
Do the electrons reside permanently in the ground state, or move to higher shell levels, like shell level 1, and permanently reside there, changing the electron eV requirement, to light, when atoms form covalent bonds, and become molecules.
Or is this completely wrong , and the electron always stays in the ground state, orbital region, in ANY element, as atoms come together, and make covelent bonds to form molecules, and just the electrons eV changes but the electron does not change to higher orbit shell regions.
I am studying neuroscience, and I am thinking hard how to make human tissue translucent by playing around, and effecting the electron, in different ways.
Doping atoms to increase, and decrease the band gap in not going to work in human tissue, and bone, I do not think is possible.
I am grateful for your help, anything helps even a few words. [:D]
[Title turned into a self-contained question - moderator]
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Do all electrons orbit in the ground state ...as atoms come together to form molecules?
It varies, depending on the particular chemicals, and the form that their chemical combination takes. In general, electrons, atoms and molecules tend towards the lowest energy state for the conditions in which they find themselves.
When you put two bar magnets together, they tend to spin around so that their North and South poles are in contact, and they stick there. This is the lowest energy state for two bar magnets. You can separate them again, but this takes more energy.
You can imagine electrons as little bar magnets. They like to line up so their North and South poles are "in contact", and they stick there. This is the lowest energy state for two electrons. You can separate them again, but this takes more energy.
Now think of a metal like Sodium. All of the electrons are in pairs, except the outermost "lonely" electron. This electron is in its own shell, and is far from the other electrons of the atom. These outer electrons form a conduction band where all these "lonely" electrons can move between atoms. If you connect a battery, the electrons will flow as a current through the Sodium. If you shine a light on the Sodium, these mobile electrons will react to the external electromagnetic field, and produce an internal counter-current which reflects the light away. So Sodium is a conductive metal which reflects light.
Now think of a gas like Chlorine. All of its electrons are in pairs, except for one of its outer electrons, which is "lonely". But if it joins up with another Chlorine atom, these lonely electrons can pair up; this is the normal state of Chlorine, as a gas formed of two chlorine atoms. These electrons form a complete shell of electrons, which is held close to the chlorine atoms, so Chlorine does not conduct electricity, or reflect light. It has a slightly greenish color, which represents certain wavelengths of light which can be absorbed to temporarily kick an electron into a higher orbit.
If you react Sodium metal and Chlorine gas*, the outer electron of the Sodium (which is held rather loosely) is ripped right off the Sodium atom, and is held very tightly by the Chlorine atom. The Sodium atom ends up with all its (remaining) electrons paired, and an overall positive charge. The Chlorine ends up with all its electrons paired (including the one kidnapped from the Sodium atom), and an overall negative charge.
The result is Sodium Chloride, or table salt. If you form it into a single large crystal, it has a large bandgap, and is clear - nothing like the original shiny Sodium Metal or greenish Chlorine gas. Dissolve it in water, and the water remains clear.
So the electron from the Sodium atom is no longer in the lowest energy state (the ground state) of the Sodium atom, because it has been kidnapped by the Chlorine atom. But taken together, Sodium Chloride has a lower overall energy state than Sodium metal and Chlorine gas, because all of the electrons are paired.
*Do not perform this experiment at home; both Sodium and Chlorine are dangerous, as are their chemical reactions.
PS: Sorry about the rampant anthropomorphism....
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The glass state is different from the crystal state. In a crystal, all the atoms are organized creating stability. While in the glass state, the atoms are more randomized but frozen that way. This means the atoms in the glass are at higher energy, while the crystal atoms are at lower energy. The higher energy of the atoms in the glass, makes the light less impactful, since the electrons are already frozen in higher energy levels. The light goes through not able to excite. The crystal's atoms are lower in energy and can be impacted; excited easier. The light gets absorbed and reflected at the beginning; opaque.
In terms of plastics, polyethylene tends to be white and opaque. This plastic is can easily form crystals. Whereas, a plastic like polypropylene, often used for clear soda bottles, will not crystalize, during the manufacturing process.
If you take clear polypropylene and stretch it, the plastic will turn white; becomes more opaque. The force and stress causes the polymer molecules to align in the direction of force, to make crystals. The force provides activation energy to allow the more stable crystal state.
A real interesting common material is vulcanized rubber. A rubber band will stretch, until a certain point, and then break. As we stretch the rubber band, the more random molecules will align toward a crystal state; material gets stronger. If we let it go, even though the stretch is more stable, like with polypropylene, it will revert back to the glass; stretches back. Polypropylene will remain all stretched out due to the stability. The difference is connected to sulfur cross links that lock in the glass state between the molecules. The sulfur atoms dominate over the crystal state. The value of this is as we stress the rubber; tire, the pushed into crystal stability, by making the rubber more stable; lower energy, make it last longer.
Rubber is a material one can use at home, to demonstrate the connection energy and entropy. As an experiment, take a rubber band and place it between your lips. As you stretch it, you will feel heat given off. The energy/heat given off, occurs,because the molecules in the rubber will align and lower entropy; forms order. The loss of entropy gives off energy; heat.
Next, keep holding the rubber band, all stretched out, until it feels room temperature on your lips. Next, let the stretch rubber band contract between your lips. You can feel it get cold. As the elastic contracts, the entropy increases again; glassy disorder. An increase of entropy, will absorb energy; gets cool on your lips. That experiment allows one to feel the entropy change between glass and crystal as well as learn about the connection between energy and entropy. This is called economy science.
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[/glow]Great thank you for your answer, I am studying neuroscience, and am thinking hard how to make human tissue more transparent/translucent.
Curing Parkinsons disease, Alzheimer's disease is my life goal.
I know I will never get 100% transparency, but to start with 2% translucency is what I am thinking hard about right now.
The key is finding ways to increase, and decrease the electrons electron voltage requirement, but their is just a few limited ways to do this, do you know all the ways to increase band gap, apart from doping atoms which can't be done in human tissue, or bone.
Thank you. [:D]
quote author=evan_au link=topic=66950.msg488365#msg488365 date=1464561630]
Do all electrons orbit in the ground state ...as atoms come together to form molecules?
It varies, depending on the particular chemicals, and the form that their chemical combination takes. In general, electrons, atoms and molecules tend towards the lowest energy state for the conditions in which they find themselves.
When you put two bar magnets together, they tend to spin around so that their North and South poles are in contact, and they stick there. This is the lowest energy state for two bar magnets. You can separate them again, but this takes more energy.
You can imagine electrons as little bar magnets. They like to line up so their North and South poles are "in contact", and they stick there. This is the lowest energy state for two electrons. You can separate them again, but this takes more energy.
Now think of a metal like Sodium. All of the electrons are in pairs, except the outermost "lonely" electron. This electron is in its own shell, and is far from the other electrons of the atom. These outer electrons form a conduction band where all these "lonely" electrons can move between atoms. If you connect a battery, the electrons will flow as a current through the Sodium. If you shine a light on the Sodium, these mobile electrons will react to the external electromagnetic field, and produce an internal counter-current which reflects the light away. So Sodium is a conductive metal which reflects light.
Now think of a gas like Chlorine. All of its electrons are in pairs, except for one of its outer electrons, which is "lonely". But if it joins up with another Chlorine atom, these lonely electrons can pair up; this is the normal state of Chlorine, as a gas formed of two chlorine atoms. These electrons form a complete shell of electrons, which is held close to the chlorine atoms, so Chlorine does not conduct electricity, or reflect light. It has a slightly greenish color, which represents certain wavelengths of light which can be absorbed to temporarily kick an electron into a higher orbit.
If you react Sodium metal and Chlorine gas*, the outer electron of the Sodium (which is held rather loosely) is ripped right off the Sodium atom, and is held very tightly by the Chlorine atom. The Sodium atom ends up with all its (remaining) electrons paired, and an overall positive charge. The Chlorine ends up with all its electrons paired (including the one kidnapped from the Sodium atom), and an overall negative charge.
The result is Sodium Chloride, or table salt. If you form it into a single large crystal, it has a large bandgap, and is clear - nothing like the original shiny Sodium Metal or greenish Chlorine gas. Dissolve it in water, and the water remains clear.
So the electron from the Sodium atom is no longer in the lowest energy state (the ground state) of the Sodium atom, because it has been kidnapped by the Chlorine atom. But taken together, Sodium Chloride has a lower overall energy state than Sodium metal and Chlorine gas, because all of the electrons are paired.
*Do not perform this experiment at home; both Sodium and Chlorine are dangerous, as are their chemical reactions.
PS: Sorry about the rampant anthropomorphism....
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Great thank you for your answer,
I thought I read something about glass be transparent has nothong to do with being amorphous, its the energy of the electrons isnt it for sure.
I am studying neuroscience, and am thinking hard how to make human tissue more transparent/translucent.
Curing Parkinsons disease, Alzheimer's disease is my life goal.
I know I will never get 100% transparency, but to start with 2% translucency is what I am thinking hard about right now.
The key is finding ways to increase, and decrease the electrons electron voltage requirement, but their is just a few limited ways to do this, do you know all the ways to increase band gap, apart from doping atoms which can't be done in human tissue, or bone.
Thank you. :D
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how to make human tissue more transparent/translucent.. do you know all the ways to increase band gap?
Curing Alzheimer's Disease is a noble goal.
But human tissue (muscle proteins, bone crystals, red blood cells, amyloid plaques and tau tangles, etc) have a certain range of bandgaps. And it's a complicated range, because these are complicated chemicals. Attempts to change this bandgap will destroy the human tissue through which you are trying to see. That is about as useful as cutting open the patient's brain (which is how they make a definitive diagnosis of Alzheimer's now - but they do have to wait until the patient is dead, for ethical reasons).
What you want is a non-destructive imaging technique. Current techniques include MRI machines and CAT scanners, which can show a decrease in brain volume.
- MRI uses radio waves, which pass through human flesh transparently, and don't change the bandgap.
- CAT Scanners use X-Rays, which pass through human tissue without changing the bandgap (although X-Rays will knock the occasional electron right out of an atom).
- More complex techniques include using an antibody which binds to the protein of interest. Labelling the antibody with deuterium should show up in an MRI machine (Alan?). Labelling the antibody with a radioactive isotope will show up in a gamma-ray camera.
- There are rodent models for Alzheimer's Disease. There are not so many ethical concerns about cutting up mouse brains.
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The electrons in atoms will attempt to find their native ground state, based on ambient energy. This ground state can be different for different ambient situations. Single atoms will behave differently, than when these atoms become part of composites like molecules, metals, ceramics and plastics. As we build larger composites of atoms, the electrons will tend to delocalize away from the original atoms so they can be shared. This may result in an excited state relative to the single atoms, but it becomes lowered energy, relative to the composite.
An analogy is a male and female may both be set in their ways; both have their optimized life style. They meet and fall in love. Now, both are in a for a surprise, since they may both need to change their ways, into something less comfortable; less optimized to their single lifestyle. However, there is an advantage to being a pair; other things become easier.
Another approach you might consider, to make the body more transparent, is to change the type of energy you use. For example, NASA can look inside the earth, all the way to the core of the earth to the other side, by means of seismic waves. This is not EM energy waves, but more like sound waves. As a side note the, they found the earth is denser north to south than east to west. The bulge of the equator is due to the innards earth being less dense east and west.
The different regions of the body should have subtle differences in density; organics, ions and water. This should impact the speed of sound. One should be able to map the innards, with no harmful impact on any tissue, since sound waves will not cause chemical reactions. Tumors and cancer may have their own acoustical properties, and look like certain instruments playing in the symphony of the body. The acoustical prelude of the song, leading to Alzheimers, may have a certain signature; chorus. This technique should allow us to learn more about disease progression. This technique may not cure, but may be limited to nondestructive diagnosis.
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Puppypower, people *do* look at the brain using ultrasound:
http://www.radiologyinfo.org/en/info.cfm?pg=ultrasound-cranial
Timemachine, as evan pointed out, trying to make the brain transparent to visible light is not going to be useful for medical imaging. The constituents of the head are mostly molecular. Not only does each molecule have its own electronic structure (different energy levels and absorptions), but molecules are fragile enough that trying to manipulate their electronic structures significantly will often result in decomposition of the molecules (this is essentially how sunlight can lead to skin cancer).
There is also the problem of the different refractive indices of the various materials. Transparency would be impossible--even if all of the materials were somehow colorless, it could only be translucent.
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As a side note the, they found the earth is denser north to south than east to west.
I also have seen reports of seismic measurements showing that the Earth's core is not exactly symmetrical, and that it is not rotating in lockstep with the surface of the Earth.
Although looking at seismograms this tends to be the domain of the US Geological Survey (USGS), rather than NASA.
The bulge of the equator is due to the innards earth being less dense east and west.
Sorry, most of Earth's equatorial bulge is due to the fact that the Earth is spinning, and centrifugal force pushes out the rocks and ocean near the equator.
(With apologies to the purists who hate centrifugal force...)
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If the electrons band gap was increased/Decreased in human tissue, to make it more translucent, how would it effect the tissue.?
Electrons get exited in human tissue all the time from light, in the absorption, and emission of light, and in hydrogen gas electrons move to higher shell levels, and when it is in a different shell level it requires a different eV from light to move to another higher shell level.
Not sure how this process happens in human tissue exactly.
You cannot dope human tissue like in inatimate material.
But if it were possible to increase, and decrease the band gap in electrons, in human tissue, how would it effect the tissue, would it destroy it, would it kill the person.
I am grateful for your help, anything helps even a few words. [:D]
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Heavy water, where the hydrogen of water are replaced by deuterium; D2O or tritium T2O, have different physical properties from common water; H2O.
Below are the ionization potentials for regular water H20, and water with the hydrogen replaced by Deuterium D20. HDO where only one hydrogen is replaced with D, has values in the middle.
Carbon compounds usually have hydrogen atoms. A similar thing will happen if H is replaced by D.
If you could inject tumors directly with D2O or even HDO, and get them to drink, they would stand out.
H2O: gas; 1216 kJ ˣ mol-1 (12.61 eV); 101,766.3 cm-1
D2O: gas 1219 kJ ˣ mol-1 (12.64 eV); 101,915.2 cm-1
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Heavy water, where the hydrogen of water are replaced by deuterium; D2O or tritium T2O, have different physical properties from common water; H2O.
Below are the ionization potentials for regular water H20, and water with the hydrogen replaced by Deuterium D20. HDO where only one hydrogen is replaced with D, has values in the middle.
Carbon compounds usually have hydrogen atoms. A similar thing will happen if H is replaced by D.
If you could inject tumors directly with D2O or even HDO, and get them to drink, they would stand out.
H2O: gas; 1216 kJ ˣ mol-1 (12.61 eV); 101,766.3 cm-1
D2O: gas 1219 kJ ˣ mol-1 (12.64 eV); 101,915.2 cm-1
Changing H for D has negligible effects on the electronic structure of molecules .H2O vs D2O is probably one of the most extreme examples, and your numbers show a 0.2% change... This would NOT lead to any significant change in the way that the molecules interact with light, and would NOT cause the tumors to stand out in any significant way other than by nuclear magnetic resonance (NMR or MRI). Substituting significant amounts of H with D in the patient's body, however, would lead to toxic effects. (of all people, puppypower, I would expect YOU to know that H and D participate slightly differently in hydrogen bonding...)
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Can you make a electron move faster, to move to a higher shell level, WITHOUT being absorbed by any EM waves absorbing.?
Edit
So without the absorption, and emission process, to move electrons to higher shell levels, can you make a electron move faster, to move to a higher shell level.
Electrons have so much energy that they whiz round too fast to fall into the nucleus.
Instead they circle the nucleus in shells (layers) at different distances, or energy levels, depending on how much energy they have.
The more energetic an electron, the farther from the nucleus it is.
I am grateful for your help, anything helps even a few words. [:D]
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Electrons have so much energy that they whiz round too fast to fall into the nucleus.
This is derived from a high-school analogy that "atoms are just like a tiny Solar System".
It's a good way to start studying atoms, but it is important that you grow out of this understanding if you are going to invent a new imaging technology.
I suggest that you start here, and then click on the link to quantum theory. Spend lots of time studying quantum theory.
https://en.wikipedia.org/wiki/Atomic_theory#First_steps_toward_a_quantum_physical_model_of_the_atom
Can you make a electron move faster, to move to a higher shell level, WITHOUT being absorbed by any EM waves absorbing.?
It takes energy to move an electron to a higher energy level.
Since the electron and proton carry an electric field, the most efficient way to impart energy to an electron is to hit it with an electromagnetic wave of the appropriate energy.
The gravitational field of an electron is so slight that trying impart energy via gravitation would be extremely destructive to your patient.
- Electrons don't respond to the strong nuclear force.
- Electrons can be produced in interactions with the weak nuclear force, but the interactions are fairly rare, and the energy levels tend to be fairly high.
A lower-energy version of this effect occurs to some extent in medical Technetium 99-m, but the short range of the electrons is not very useful for medical imaging. The main decay mode is low-energy gamma rays, which are useful for medical imaging because they are detectable outside the body. But the energies here are 140,400eV compared to the 1-3eV that you seek.
See: https://en.wikipedia.org/wiki/Technetium-99m
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You can excite electrons by shooting them with other electrons. There are several materials that fluoresce or phosphoresce in the visible region when subjected to a cathode ray (https://en.wikipedia.org/wiki/Phosphor#Principles)
I would NOT recommend trying to make people transparent by bombarding them with cathode rays!!!
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Thank you for the links [:D]
quote author=evan_au link=topic=67027.msg488856#msg488856 date=1465079426]
Electrons have so much energy that they whiz round too fast to fall into the nucleus.
This is derived from a high-school analogy that "atoms are just like a tiny Solar System".
It's a good way to start studying atoms, but it is important that you grow out of this understanding if you are going to invent a new imaging technology.
I suggest that you start here, and then click on the link to quantum theory. Spend lots of time studying quantum theory.
https://en.wikipedia.org/wiki/Atomic_theory#First_steps_toward_a_quantum_physical_model_of_the_atom
Can you make a electron move faster, to move to a higher shell level, WITHOUT being absorbed by any EM waves absorbing.?
It takes energy to move an electron to a higher energy level.
Since the electron and proton carry an electric field, the most efficient way to impart energy to an electron is to hit it with an electromagnetic wave of the appropriate energy.
The gravitational field of an electron is so slight that trying impart energy via gravitation would be extremely destructive to your patient.
- Electrons don't respond to the strong nuclear force.
- Electrons can be produced in interactions with the weak nuclear force, but the interactions are fairly rare, and the energy levels tend to be fairly high.
A lower-energy version of this effect occurs to some extent in medical Technetium 99-m, but the short range of the electrons is not very useful for medical imaging. The main decay mode is low-energy gamma rays, which are useful for medical imaging because they are detectable outside the body. But the energies here are 140,400eV compared to the 1-3eV that you seek.
See: https://en.wikipedia.org/wiki/Technetium-99m
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Thank you for the links [:D]
You can excite electrons by shooting them with other electrons. There are several materials that fluoresce or phosphoresce in the visible region when subjected to a cathode ray (https://en.wikipedia.org/wiki/Phosphor#Principles)
I would NOT recommend trying to make people transparent by bombarding them with cathode rays!!!