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Do electrons or protons or any other elementary particle have colors of their own or do they have smell?

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    $\begingroup$ But why do they dont have any color or smell? $\endgroup$
    – user10379
    Jan 13, 2016 at 19:25
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    $\begingroup$ Why should they have a color and a smell?!? $\endgroup$
    – MaxW
    Jan 13, 2016 at 19:49
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    $\begingroup$ Books showing colorful images, using color to highlight elements in chemical formulas just want to make a visually noticeable difference between those elements, and (hopefully) don't intend on how those things look like. They don't have a color of their own (werrrrrl, mostly), unless coupled with other tings. $\endgroup$ Jan 13, 2016 at 20:41
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    $\begingroup$ I'm voting to close this question as off-topic because huh? $\endgroup$
    – Todd Minehardt
    Jan 14, 2016 at 0:58
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    $\begingroup$ The color is the interesting part here. They should react with photons to have any color. By molecules the chemical bonds can absorb some frequencies of the light, that why they have color. In theory a single electron or proton should be able to absorb photons too, so they might have color, but not necessary in the visual range of frequencies. $\endgroup$
    – inf3rno
    Jan 14, 2016 at 7:18

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You can understand why they don't by understanding how smell and vision work

The mechanism by which we (or other animals) smell is not fully understood. But the key is that receptors in your nose are activated when certain molecules interact with them. The receptors consist of a wide variety of complex proteins with cavities of particular shapes. The cavities also have different patterns of surface structures which interact with the target molecules in a variety of ways (there might be some polar patches, patches that can hydrogen bond to another molecule and some that prefer non-polar interaction). When an appropriate target fits into the cavity, the cavity can send signals to nerves to signal that a target has been recognised. The targets can be very specific and there are a lot of different types.

Elementary particles don't (usually) exist alone but only as parts of other atoms or molecules. So they won't smell. We haven't evolved ways to detect free elementary particles. It is the 3D structure of molecules that creates smell.

The mechanism of sight is simpler. Molecules in the eye can absorb particular frequencies of light and then send a signal to the nervous system that they have detected some type of light. Light consists of photons. We see light when something emits photons, but only a narrow range of photons of about one octave. We can't see radio waves or X-rays as our eyes are not built to do detect potions of those energies. We see colour because photons of different energies can excite different receptors in the eye (human eyes have three different detectors tuned to red, green and blue light).

What creates coloured light is the either the emission of photons of the right energy or the selective absorption of light coming from another source. selective absorption happens when there is some way for the thing absorbing the light to capture the incoming photon's energy. This only happens when there is some part of the absorbing entity that can shift from one energy level to another and where that energy level matches the energy of the incoming photon. Some molecules have that property, but in many the energy levels don't match anything in visible light so they don't show colour.

Elementary particles don't have any energy levels in the appropriate range so won't be coloured. In molecules that do have energy levels absorption can happen, but this is a property of the whole molecule, not the atoms that make it up. It isn't the atoms that have colour, it's the molecule. Also atoms are about the same size as wavelengths of light, so even if you had a powerful microscope you could not see the individual components using light so the idea of them having colour makes no sense.

When presenting models of molecules, chemists often draw the atoms in different colours. But this is so they can tell them apart and in no way represents what an imaginary microscope would see. The colours are entirely arbitrary.

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Electrons and protons do not have a smell because that means that they would have to reach our nose, which have molecule sized receptors, and cannot fit in the receptors.

Electrons and protons cannot have color since they sare smaller the visible light themselves! So how can they reflect something much bigger than themselves?

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    $\begingroup$ As far as I know, electrons are one of the most stable things in universe. And proton decay is still a matter of research. $\endgroup$ Jan 13, 2016 at 20:59
  • $\begingroup$ @GyroGearloose electrons would be stable in pure vacuum for sure. $\endgroup$
    – TanMath
    Jan 13, 2016 at 20:59
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    $\begingroup$ @_TanMath everything can be tackled if not in pure vacuum and attacked with some high energy particle. $\endgroup$ Jan 13, 2016 at 21:03
  • $\begingroup$ So what do you reefer by "electrons and protons can be unstable by itself". I read "itself" as "not interacting with something else" $\endgroup$ Jan 13, 2016 at 21:05
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I think it is pretty clear that electrons per se have no color and are invisible . If you have a glass tube with a wire at each end and connect the ends to a high voltage power source, electrons do not flow. When you pump the air out of the tube until you have a pretty good vacuum, the electrons begin to flow and the tube emits light, due to collisions of the electrons with the atoms in the tube followed by decay of those excited atoms back to the ground state--the atoms are emitting the light, not the electrons themselves. (For example, if sodium atoms are present you get yellow light, and if mercury is present you get mostly ultraviolet light.) But - if you keep pumping on the tube until you have an almost perfect vacuum, the electrons still flow (you can measure that with an ammeter in the circuit) but there is no light. They are invisible.

If you dissolve sodium metal in liquid ammonia, you get a deep blue color. Some people would say that is the color of "solvated electrons", but they are not actually free electrons. It is believed that the result is ammonia-solvated sodium cations and ammonia-solvated ammonia radical anions. The blue color is due to absorption of visible light by the latter.

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  • $\begingroup$ Who believes that the electron is associated with a specific ammonia molecules to form a radical anion? Usually I see it in print as an electron sitting in a cavity between ammonia molecules. $\endgroup$ Apr 14, 2021 at 16:04
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According to Physicists find that an ultrahigh-energy proton looks like a black disk

What does a proton look like? The common answer to this question is that protons are much too small to scatter light, and since light is necessary for us to see things, protons do not “look” like anything. But in a new study, physicists have gathered sufficient evidence to show that, at least at very high energies, the proton is a black disk – sort of an elongated hockey puck.

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