Neon is a chemical element that has the symbol Ne and atomic number 10. It is a noble gas that is colorless, odorless, inert, and monoatomic. Neon was discovered in 1898 by the Scottish chemists William Ramsay and Morris Travers. Here are two interesting facts about neon:
Fact 1: Neon Gives Off an Orange-Red Glow When Electrically Charged
Neon gas glows bright orange-red when placed in a high voltage electrical discharge. This occurs because electricity excites the electrons in the neon atoms, causing them to jump up energy levels. When the electrons fall back down, they emit photons in the orange-red part of the visible spectrum.
This glow is what gives neon lighting its distinctive color. Neon lights and signs work by running an electrical current through tubes filled with neon gas. The electricity excites the neon, making it glow its brilliant reddish-orange. Neon’s glow is so intense that just a small amount of it is needed in neon lamps and signs.
The exact color that neon emits depends on the gas pressure inside the tube. At low pressures, the glow shifts more towards red. As the pressure increases, the color becomes more orange. The colors can range from deep red at around 1 Torr to orange-red at 20 Torr. But at typical commercial pressures of 4–8 Torr, the most common sign color of orange-red is produced.
So in summary, the vivid reddish-orange glow of electrically charged neon gas is what makes it useful for signs and lighting. This vivid glow occurs when electrons in the neon atoms get excited by electricity and then release photons when falling back down to their ground state.
Fact 2: Neon is Used in Fluorescent Lamps
Neon is one of the types of gas used to make fluorescent lamps and tubes glow. Within these lamps, neon emits a reddish-orange light when excited by electricity. But neon isn’t used alone in fluorescents. It is mixed with other gases like argon, mercury vapor, and phosphors to produce the range of colors emitted by fluorescent lighting.
Here’s how it works: an electric current excites mercury vapor atoms inside the fluorescent tube. When the mercury atoms get excited, they produce ultraviolet photons as they return to their ground state. The ultraviolet light is invisible but contains a high amount of energy. This UV light strikes the phosphor coating on the inside of the tube, causing the phosphors to absorb the energy and emit visible light.
Different phosphor compounds emit different colors. For example, blue phosphors emit blue light, and red phosphors give off red light. By blending phosphors, any color can be created. The neon gas aids this process by emitting its own reddish-orange light and energizing the mercury atoms. The argon gas helps regulate the electrical discharge.
So fluorescent lamps mix the colors produced by phosphors with the neon’s orange-red to create a wide gamut of possible shades. Neon gives the distinctive tint to fluorescent lighting that makes it recognizable. Neon lamps tend to have better color rendering than those without neon.
So in summary, fluorescent lamps exploit neon’s glow to produce their illuminating effects. The neon provides its own reddish light while also energizing the mercury vapor atoms that make the phosphors radiate color.
Discovery of Neon
Neon was discovered in 1898 by the Scottish chemist William Ramsay and English chemist Morris Travers while they were working at University College London. They had successfully isolated the noble gases argon and krypton in previous experiments. Ramsay suspected that another noble gas element existed between the two, based on the periodic table’s arrangement.
To search for the predicted element, Ramsay and Travers extracted residue gas from liquid air. When they analyzed the gas spectroscopically, they observed a bright red spectral line that did not match any known element. This indicated the presence of a new element, which they named “neon” after the Greek word νέον meaning “new one.”
Later that year, Ramsay was able to isolate enough neon to determine it was colorless, odorless, chemically inert, and consists of monatomic molecules (Ne). Travers then determined neon’s atomic weight of 20.2. They announced their discovery jointly to the British Chemical Society.
Along with helium, neon was the second noble gas discovered. It joined the other known noble gases of argon, krypton, and xenon (radon was later identified in 1898). The discovery of neon provided further evidence of the periodic law and existence of elemental groups, like the noble gases.
Properties of Neon
Neon is the fifth most abundant chemical element in the universe. Here are some key properties of neon:
- Atomic number: 10
- Atomic symbol: Ne
- Atomic weight: 20.1797
- Density: 0.9002 g/L at 0°C
- Melting point: -248.59°C
- Boiling point: -246.08°C
- Color: Colorless
- Phase at room temperature: Gas
- Number of protons/electrons: 10
- Number of neutrons: 10
- Classification: Noble gas
- Electron configuration: 1s2 2s2 2p6
As a noble gas, neon has a full outer electron shell, making it stable and resistant to forming compounds. It has the narrowest liquid range of any element and the second lowest melting and boiling points.
Neon’s Uses
Some of the main uses of neon include:
- Signs and advertisements – Neon lighting is produced by filling glass tubes with neon gas and running an electric charge through them.
- Lighting – Besides signs, neon lights are used in electronics and laser technology.
- Refrigerant – Liquid neon can provide rapid cooling and is used in some cryogenic applications.
- Television tubes – Small amounts of neon are used in plasma TVs.
- Night lights – Neon glow lamps provide low-level illumination.
- Voltage indicator – Neon lamps light up when a threshold voltage is reached, making them useful voltage indicators.
- Lasers – Helium-neon lasers produce a red beam widely used in barcode scanners.
The most common use of neon is in neon signs and lights, which rely on neon’s reddish-orange glow when electrified to form vibrant advertisements and decorations. Beyond lighting, neon has applications in refrigeration, voltage indication, television screens, and lasers.
Occurrence and Production
Neon makes up about 0.0018% of the Earth’s atmosphere by volume. It’s the 5th most abundant element in the universe, but rare on Earth. Neon doesn’t naturally form many compounds due to its nobility.
Neon is extracted from liquefied air. The air is cooled to cryogenic temperatures, causing it to liquefy. Liquefied air is then allowed to evaporate so that the boiling points separate the gases by atomic mass. The neon boils off at the appropriate fraction. Once separated, impurities are removed from the neon via adsorption.
Most neon production happens in Ukraine, Russia, and the United States. Neon costs about $25 per liter, making it relatively expensive since extraction requires cryogenic distillation of huge amounts of air.
Neon in its Elemental Form
At standard temperature and pressure, neon exists as a colorless, inert monoatomic gas. Here are some key properties of pure neon gas:
- Density: 0.8991 g/L
- Refractive index: 1.000273
- Specific heat capacity: 1.03 J/g-K
- Thermal conductivity: 0.0491 W/m-K
- Viscosity: 3.19 uPa-s
In its pure state, neon is non-toxic. It is tasteless, odorless, and colorless.
As a noble gas, neon is chemically unreactive due to its full outer electron shell. However, some metastable neon compounds form at extreme temperatures or pressures. These include neon fluorides such as NaFNe, and excimers like NeAr, NeKr, NeXe, and Ne2.
At very low temperatures, neon can condense into a liquid state. Liquid neon has a density of 1.207 g/mL and solidifies at 24.56 K. Solid neon has a cubic crystal structure.
Chemical Properties
As a noble gas, neon is generally inert and does not form stable compounds under normal conditions. However, there are some chemical properties of neon:
- Does not readily react or form compounds due to having a full valence shell.
- At extreme pressures, can form compounds with fluorine and oxygen, such as NeF2, NeF4, NeO, and NeO3.
- Can form excimers with other noble gases, including neon excimers like Ne2.
- Metastable neon atoms can form temporary bonds with metals, halogens, and some other elements.
- Dry neon gas is non-corrosive and non-toxic.
So while neon is largely non-reactive, it can participate in a few chemical reactions under certain conditions like high pressures. Compressed neon gas mixtures should be handled with care as chemical reactions with the other gases become more likely.
Isotopes of Neon
Neon has three stable isotopes along with two longer-lived radioactive isotopes.
| Isotope | Natural Abundance | Atomic Mass |
|---|---|---|
| Ne-20 | 90.48% | 19.99 u |
| Ne-21 | 0.27% | 20.99 u |
| Ne-22 | 9.25% | 21.99 u |
| Ne-21 | Trace | 21.99 u |
| Ne-22 | Trace | 22.99 u |
The most common isotope, Ne-20, makes up almost 91% of natural neon. The other stable isotopes have very low natural abundances. The radioactive nuclides have half-lives too short to allow substantial accumulation.
Electron Configuration
Neon has 10 electrons and 10 protons in its atom. Its electron configuration is:
1s2 2s2 2p6
This represents the occupation of the electron shells of neon. The first shell (1s) has 2 electrons. The second shell (2s and 2p) is filled with 8 electrons.
The full 2p subshell makes neon’s outer electron shell complete. This stable configuration is why neon is inert, as it already has a complete octet.
The electron configuration results from neon having 10 total electrons, distributed as 2 in the first shell, 2 in the second shell s orbital, and 6 in the second shell p orbital. The p orbital is filled, completing the outer shell.
History of Neon
Some key events in the history of neon:
- 1898 – Neon is discovered by William Ramsay and Morris Travers.
- 1902 – Georges Claude creates the first neon lamp and bends tubes into letters to make the first neon signs.
- 1910 – Claude exhibits neon signs in Paris, introducing neon lighting to the public.
- 1912 – Claude patents the neon sign and starts selling them commercially.
- 1920s – Neon signs gain popularity in the US; the first neon sign in Times Square is installed.
- 1960s – Neon usage expands beyond signage into electronics and lasers.
- 2000s – Advances in LED lighting provide more efficient alternatives to neon signs.
So neon lamps were pioneered in the early 20th century, creating a revolution in lighting and signage. Their novelty made neon signs iconic fixtures in cities like Las Vegas and Times Square. While less common today, neon lighting remains a decorative element in architecture.
Beyond signage, neon found important uses in technologies like lasers, television, and refrigeration in the latter 20th century. It took nearly 50 years after its initial discovery for all its applications to fully emerge.
Conclusion
In summary, here are two key facts about neon:
– Neon has a distinctive reddish-orange glow when electrified. This occurs as electrons emit photons when dropping to lower energy states. This allows neon to be used in fluorescent lighting and vivid neon signs.
– Neon is one of the noble or inert gases. Its full outer electron shell makes it resistant to bonding with other elements. This chemical stability makes purified neon non-reactive and non-toxic.
Neon’s unique properties have made it important for lighting, signs, lasers, and refrigeration. Its discovery helped demonstrate the predictive power of the periodic table and quantum mechanics in understanding chemical elements. Over a century after its initial discovery, neon continues to have high-tech applications alongside more decorative roles in illumination.
