Welcome to another instalment of the Element of the Month – a regular feature on the Radleys blog where we take a good long look at one of the 118 (and counting) elements of the periodic table. How do we choose our element of the month? It’s simple! We use a random number generator to produce a figure between 1 and 118. This month we got number 10, which makes neon (Ne) our 13th element of the month. Neon – The Key Facts Neon is the fifth most abundant element in the universe after hydrogen, helium, oxygen, and carbon. It’s a noble gas with an atomic number of 10. It’s about two thirds the density of air, and it’s colourless, odourless, inert, and monatomic under standard conditions. Once nitrogen, oxygen, argon, and carbon dioxide have been removed, neon is one of the three residual rare inert elements remaining in dry air. The other two are krypton and xenon. Large volumes of neon are built up during the alpha-capture fusion process in stars. However, it is very rare on Earth. Indeed, neon is rare on all inner terrestrial planets, simply because it’s highly volatile and incapable of forming compounds that could fix it to solids. Also, because it’s lighter than air, it escapes from Earth’s atmosphere. The Discovery of Neon Neon was discovered in London in 1898 by a pair of British chemists: Sir William Ramsay and Morris W. Travers. Ramsay chilled a sample of air until it became a liquid. He then warmed this liquid, capturing the gases as they boiled off. Nitrogen, oxygen, and argon had already been identified. Over a six week period, Ramsay and Travers then isolated the remaining gases in order of abundance. First, they discovered krypton. But once this had been removed, they had a gas that gave a brilliant red light under spectroscopic discharge. This was neon, and it was given its name by Ramsay’s son. The term neon comes from the Greek analogue of “novum”, which means “new”. Neon Lights When most people think of neon, they think of lights. Neon lights started life as “Moore tubes”. These devices take their name from American engineer Daniel McFarlan Moore, who developed a glow discharge lighting system while working for General Electric. A Moore tube is a glass tube from which the air has been removed and replaced by a different low-pressure gas that glows when a current is passed through it. Moore tubes used nitrogen or carbon dioxide as the luminous gas. This was partly due to the scarcity of neon, but also because, when a current is passed through carbon dioxide, it emits the sort of white glow that could be used to light a room. But from 1902, Georges Claude’s company Air Liquide began to produce industrial quantities of neon as a by-product of air liquidation. In 1910 Claude demonstrated the modern neon light as we know it. He intended it for domestic use, but homeowners were put off by the red colour. However, the neon light was embraced by the advertising world, who saw its potential for creating outlandish displays. Not All Neon Lights are Neon There are actually two different kinds of neon lights. The kind that people picture when they hear the word “neon” involve luminous glass tubing that typically operate as around 2 – 15 kilovolts. Though all such lights are generally referred to as “neon lights”, any light that doesn’t glow that distinctive red colour doesn’t contain neon. It will either use a different noble gas, or else some kind of coloured fluorescent lighting. The other kind of neon lights are neon glow lamps. These tiny lamps operate at around 100 – 200 volts. Before the mass implementation of light emitting diodes (LEDs) they were widely used in circuit testing equipment and as power-on indicators. Neon glow lamps were also the forerunners of plasma displays. So that’s neon! The noble gas that’s incredibly abundant in the universe but incredibly rare on Earth. Yet despite its scarcity, it’s one of the few elements that most people can readily picture.