Neon is a Noble Gas that's atomic symbol is Ne, and atomic number is 10. It's most common Isotope is Neon-20 (abbreviated Ne20), which has 10 Protons and 10 Neutrons, however there are small percentages of Ne21 and Ne22. The electron configuration of the Neon atom is simply 2, 8.
Being a Noble Gas, Neon is very non-reactive, due to the fact that all of the Noble Gases have a "comfortable" number of electrons, and almost never require any or have any extra. This makes there not many uses for Neon, because there are no natural compounds, Neon only ever occurs in it's pure form. Some scientists have managed to make very basic compounds with other Noble Gases, but not for Neon.
The most well known, and I believe most common use for Neon gas is in lighting, as low-pressure Neon will glow bright orange when high voltage is applied. You've probably seen Neon signs, although not all Neon signs have Neon gas, only a redish-orange color (Which you might've noticed is one of the most common colors in Neon signs) Neon signs consist of long tubes full of low-pressure Neon, with an electrode(Metal bar connected to a wire that goes through the glass) at either end. When high voltage is applied to the electrodes, electrons arc through the Neon gas from one electrode to the other, which Ionizes the Neon atoms causing them to release light.
This "Arc" is similar to a spark you might get from scuffing on carpet with socks on, but since the Neon is under a vacuum (very low pressure), the arc gets more "fuzzy" and not such a sharp streak of light as seen in normal air, which makes it a more pleasing light source. The vacuum also lowers the voltage required to make the Neon ionize.
Neon is not the only gas that lights up like this, almost any gas under a vacuum will light up similar to Neon. Normal air under a vacuum (Which is 78% Nitrogen, 20% Oxygen, and small percentages of others) will light up a blue-purple color, but Neon is much brighter, which is why it's more commonly used.
An interesting note about Neon, and most of the Noble Gases, is that since they do not form compounds, they are most commonly found in very small percentages in normal Air. The process to purify Neon from the air is to cool the air down so cold, that the gases in it start to turn to liquids(Every element will go from solid to liquid to gas as you heat it up, since Neon is naturally a gas, cooling it puts it back to liquid stage, similar to cooling steam to get water). Since every gas turns to liquid at a different temperature, they simply cool it down slowly, and sort out the different gases as they liquify. This process can yield Nitrogen, Oxygen, Carbon dioxide, Neon, Argon, and a number of other gases, in very pure form.
Here are some Neon bulbs I managed to photograph:
This is an old bulb manufactured by General Electric, it is the same shape and size as a regular light bulb and even screws into a regular socket, but instead of a thin Tungsten filament, it has two Electrodes (The two half circles) and is filled with low pressure Neon. The high voltage from normal house wiring is enough to make it arc through the Neon, causing the familiar orange glow like in Neon signs. These bulbs are quite rare today, and I'm lucky to have access to them.
This is a small Neon "indicator" bulb, it's barely 1/4 inch in diameter. It's called an indicator bulb because it was used in houses to indicate things in the dark, and it's Neon because there was too high voltage for normal light bulbs. Illuminated light switches very commonly have a bulb exactly like these in them, you can tell if it's Neon if it's orange (Like below) and if it seems to flicker slightly.
It's not turned on as you can see, but you can clearly see the two electrodes inside the bulb. They are not touching, because when the light is turned on, electrons must arc through Neon gas (contained in the bulb) to complete the circuit, and this arc causes the Neon to light up. See below for it turned on!
These two bulbs are indicator bulbs like above, and are also very small, about the size of a bulb from those strings of Christmas lights. Only the orange one is Neon, and you can see, it has the same kind of electrodes inside as above. The glass bulb is once again filled with low pressure Neon gas. Since DC (Direct current) electricity is being used, only one of the electrodes lights up.
The blue bulb is actually very similar inside, but it has a different gas mixture which creates Ultraviolet light, which is invisible to the human eye. In order for it to glow visibly, the inside of the glass bulb is coated with special compounds, that turn Ultraviolet light into normal visible light, called "phosphors" (Not to be confused with the element "Phosphorous"). This coating is why the bulb appears opaque, not clear like the Neon one. These phosphors are used because the bulb can be made to glow almost any color, unlike Neon, which is always orange. I've seen green, blue, white, and yellow with phosphors though.
This concludes my post on Neon, thanks for reading!
~Ben
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