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Helium was named after Helios — the Greek Titan of the Sun — because it was first observed when analysing sunlight during a solar eclipse in Helium is one of the seven elements known as noble gases. Noble gases have the exact amount of electrons to completely fill the space around their atomic nucleus.
In older models, electrons are shown in shells. Helium atoms have two electrons in their outer shell and the other noble gases have eight electrons in their outer shell. The current model depicts the electrons moving in space around the nucleus in a more cloud-like formation and not set in fixed shells. As a result, noble gases are stable.
The noble gases are located in the far right column of the periodic table of elements — in group column The term may have come from noble metals — gold, silver and copper. These metals are not as reactive as other metals, and in the old days, only aristocratic noble people could afford objects made from them. Fortunately, the chemistry of noble gases is more precise than their etymology word origin! Helium is the second most abundant element in the universe.
Most of this helium was formed within minutes of the Big Bang. Recreating the process on earth may be the answer to our energy problems in the future. Since helium makes up about a quarter of the mass of the sun, it is not surprising that its presence was detected there over years ago. What is perhaps surprising, is that helium was discovered in space 26 years before it was found on earth. It has been known for hundreds of years that certain elements impart characteristic colours to a flame - a fact crucial to the coloured fireworks that we enjoy.
Copper, for example, gives a green colour, whereas sodium gives a yellow colour. It is actually possible to identify elements by the careful examination of such coloured flames.
The light is split up into a spectrum using a prism or diffraction grating in an instrument called a spectroscope. Rather than seeing a continuous rainbow of colours, a series of sharp coloured lines is formed.
This series of lines is characteristic of the particular element and acts as a sort of fingerprint. In the 19th century, scientists turned their spectroscopes to the sun and began to detect certain metals there, including sodium, magnesium, calcium and iron. In two astronomers, Janssen and Lockyer, independently noticed some very clear lines in the solar spectrum that did not match up to any known metals.
While other astronomers of the time were unsure, Lockyer suggested these unidentified lines belonged to a new metal which he named Helium after the Greek personification of the sun, Helios. For over 20 years, no sign of the metal helium was detected on earth and Lockyer began to be mocked for his mythical element. However, in the chemist William Ramsay detected helium in the gas given out when a radioactive mineral of uranium was treated with acid.
The helium formed from the radioactive decay had been trapped in the rock but liberated when the rock was dissolved away in the acid. Finally Lockyer's element had been discovered on earth, but it was no metal, rather an extremely unreactive gas.
To this day, helium remains the only non-metal whose name ends with the suffix -ium, an ending otherwise exclusively reserved for metals. Aside from being used to fill balloons, both for our entertainment, and for more serious purposes, such as for weather balloons, helium is used in other applications which depend on its unique properties. Being so light, and yet totally chemically inert, helium can be mixed with oxygen in order to make breathing easier.
This mixture, known as heliox, can help save new-born babies with breathing problems, or help underwater divers safely reach the depths of the oceans. At minus degrees centigrade, liquid helium has the lowest boiling point of any substance.
Because of this, it is used to provide the low temperatures needed for superconducting magnets, such as those used in most MRI scanners in hospitals. In many facilities where helium is used, it is captured and reused. If it isn't, it escapes into the air. But it doesn't simply accumulate in the atmosphere. Helium is so light that it can escape the pull of the earth's gravitational field and leave our planet forever. This is the fate of the helium in our balloons. Whereas it may be possible to reclaim and recycle other elements that we have used and discarded, when we waste helium, it is lost for good.
In years time, people will look back with disbelief that we wasted this precious, unique element by filling up party balloons. Cambridge University's Peter Wothers telling us the tale of element number two, Helium.
Next time we're off to 18 th century Scotland and an element that was the wrong colour. In , an intriguing mineral came to Edinburgh from a Lead mine in a small village on the shores of Loch Sunart, Argyll. At that time, the stuff was thought to be some sort of Barium compound.
Other chemists, such as Edinburgh's Thomas Hope later prepared a number of compounds with the element, noting that it caused the candle's flame to burn red, while Barium compounds gave a green colour. And that's because it wasn't Barium at all, it was Strontium and Richard Van Noorden will be here to explain how, amongst other things, it's shown us that Roman gladiators weren't meat eaters they were in fact vegetarians.
That's next week's Chemistry in its Element and I hope you can join us. I'm Chris Smith, thank you for listening and goodbye. Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists. There's more information and other episodes of Chemistry in its element on our website at chemistryworld. Click here to view videos about Helium.
View videos about. Help Text. Learn Chemistry : Your single route to hundreds of free-to-access chemistry teaching resources. We hope that you enjoy your visit to this Site. We welcome your feedback. Data W. Haynes, ed. Version 1. Coursey, D. Schwab, J. Tsai, and R. Dragoset, Atomic Weights and Isotopic Compositions version 4. Periodic Table of Videos , accessed December Podcasts Produced by The Naked Scientists. Download our free Periodic Table app for mobile phones and tablets.
Explore all elements. D Dysprosium Dubnium Darmstadtium. E Europium Erbium Einsteinium. F Fluorine Francium Fermium Flerovium. G Gallium Germanium Gadolinium Gold. I Iron Indium Iodine Iridium.
K Krypton. O Oxygen Osmium Oganesson. Muonic helium, which has the same mass as this isotope, lasts long enough to react with a hydrogen molecule. The helium atoms captured the muons, then pulled hydrogen atoms away from the molecular hydrogen and bonded with them. The team compared how long this took with the rate of the same reaction using normal hydrogen, and with a reaction rate recorded in when a type of ultra-light hydrogen, called muonium, was used.
As expected, the reaction with the disguised helium was the slowest, followed by normal hydrogen, then the light hydrogen. The way any physical system changes with time can, in theory, be predicted from the quantum states of its particles.
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