Glossary Data for this section been provided by the British Geological Survey. Relative supply risk An integrated supply risk index from 1 very low risk to 10 very high risk. Recycling rate The percentage of a commodity which is recycled.
Substitutability The availability of suitable substitutes for a given commodity. Reserve distribution The percentage of the world reserves located in the country with the largest reserves. Political stability of top producer A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators. Political stability of top reserve holder A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators.
Supply risk. Relative supply risk 4. Young's modulus A measure of the stiffness of a substance. Shear modulus A measure of how difficult it is to deform a material. Bulk modulus A measure of how difficult it is to compress a substance. Vapour pressure A measure of the propensity of a substance to evaporate. Pressure and temperature data — advanced. Listen to Potassium Podcast Transcript :. You're listening to Chemistry in its element brought to you by Chemistry World , the magazine of the Royal Society of Chemistry.
Hello, this week the story of the first alkaline metal ever isolated, why it's an alkaline metal at all and why its symbol begins with the letter K. Here's Peter Wothers. Potassium - the only element named after a cooking utensil. It was named in by Humphry Davy after the compound from which he isolated the metal, potash, or potassium hydroxide. An extract from the s by the Dutch chemist Herman Boerhaave describes how potash got its name:. It is prepared there from the Wood of green Fir, Pine, Oak, and the like, of which they make large piles in proper Trenches, and burn them till they are reduced to Ashes These ashes are then dissolved in boiling Water, and when the Liquor at top, which contains the Salt, is depurated, i.
This, then, is immediately put into large copper Pots, and is there boiled for the space of three days, by which means they procure the Salt they call Potas, which signifies Pot-Ashes on account of its being thus made in Pots.
Even earlier in the 16th Century, Conrad Gesner tells us that "Of the hearbe called Kali, doe certayne prepare a Salt". He describes this plant, Kali whose Latin name is Salsola kali but is more commonly known as Saltwort:. His method of production of this Salt of Alkali is pretty similar to that described by Boerhaave with both processes actually yielding an impure mixture of what we would now call potassium and sodium carbonate; the wood ash method yielding more potassium carbonate, potash, the salty herbs giving more sodium carbonate, soda.
However, it is from the herb kali, that we owe the word that describes both - al-kali or alkali; the 'al' prefix simply being Arabic definite article 'the'. The crude potash can be made more caustic or 'pure' by treating a solution of it with lime water, calcium hydroxide. The potassium carbonate and calcium hydroxide solutions react with a bit of chemical partner-swapping: insoluble calcium carbonate or chalk precipitates out, leaving a solution of potassium hydroxide.
It was from this pure hydroxide that Davy first isolated the metal potassium. To do this he used the relatively new force of electricity. After unsuccessfully trying to electrolyse aqueous solutions of potash, during which he only succeeded in breaking apart the water, he reasoned that he needed to do away with the water and try to electrolyse molten potassium hydroxide. This he did on the sixth of October, using the large Voltaic pile he had built at the Royal Institute in London.
His younger cousin, Edmund Davy, was assisting Humphry at the time and he relates how when Humphry first saw "the minute globules of potassium burst through the crust of potash, and take fire as they entered the atmosphere, he could not contain his joy". Davy had every right to be delighted with this amazing new metal: it looked just like other bright, shiny metals but its density was less than that of water.
This meant the metal would float on water --at least, it would do if it didn't explode as soon as it came into contact with the water. Potassium is so reactive , it will even react and burn a hole through ice. This was the first alkali metal to be isolated, but Davy went on to isolate sodium, calcium, magnesium and barium.
Whilst Davy named his new metal potassium after the potash, Berzelius, the Swedish chemist who invented the international system of chemical symbols now used by chemists the world over, preferred the name kalium for the metal, better reflecting its true origins, he thought.
Hence it is due a small salty herb that we now end up with the symbol K for the element pot-ash-ium, potassium. Arsenic gets its name from a Persian word for the yellow pigment now known as orpiment. For keen lexicographers apparently the Persian word in question Zarnikh was subsequently borrowed by the Greeks for their word arsenikon which means masculine or potent.
On the pigment front, Napoleon's wallpaper just before his death is reported to have incorporated a so called Scheele's green which exuded an arsenic vapour when it got damp. So potent or not, licking the wallpaper in Napoleon's apartments is definitely off the menu. That's Bea Perks who will be with us next time to tell us the deadly tale of arsenic, 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 Potassium. 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. U Uranium. V Vanadium. X Xenon. Y Yttrium Ytterbium.
Z Zinc Zirconium. Membership Become a member Connect with others Supporting individuals Supporting organisations Manage my membership. Potassium is pronounced as poh-TASS-ee-em.
Although potassium is the eighth most abundant element on earth and comprises about 2. Metallic potassium was first isolated by Sir Humphry Davy in through the electrolysis of molten caustic potash KOH.
A few months after discovering potassium, Davy used the same method to isolate sodium. These minerals are often found in ancient lake and sea beds. Caustic potash, another important source of potassium, is primarily mined in Germany, New Mexico, California and Utah. Pure potassium is a soft, waxy metal that can be easily cut with a knife. It reacts with oxygen to form potassium superoxide KO 2 and with water to form potassium hydroxide KOH , hydrogen gas and heat.
Enough heat is produced to ignite the hydrogen gas. To prevent it from reacting with the oxygen and water in the air, samples of metallic potassium are usually stored submerged in mineral oil. Potassium, along with its partner in crime, sodium, is crucial for maintaining blood pressure, among its others activities in the body.
As such, the U. Department of Agriculture recommends that adults eat 4. Potassium doesn't get as much attention as sodium in the popular press, but it's extremely important, said Sylvia Wassertheil-Smoller, a professor emerita of epidemiology at the Albert Einstein College of Medicine in New York.
In September , Wassertheil-Smoller and her colleagues found that a diet high in potassium was linked to fewer strokes in postmenopausal women. Overall, women who ate the most potassium in their diets were 12 percent less likely to have a stroke during the year study period.
Notably, Wassertheil-Smoller told Live Science, potassium's protective effect "went beyond blood pressure. Among women with normal blood pressure, those who ate the most potassium were 21 percent less likely to have a stroke than those who ate the least. Potassium is in a lot of foods, Wassertheil-Smoller said, most famously bananas. It's also in potatoes , leafy greens, salmon, apricots, squash, tomato paste and milk. But chances are you aren't reaching the recommended consumption of this nutrient.
Other countries didn't do much better: Only about 5 percent of Mexicans, 23 percent of people in France and 8 percent of Brits managed to eat enough potassium. The data confirm that people don't get enough potassium for optimal health, said study researcher Adam Drewnowski, an epidemiologist at the University of Washington.
On the other hand, the low rate of compliance with the recommendations suggests that the goals are unfeasible, Drewnowski said in a statement.
Likewise, among the older women in Wassertheil-Smoller's study, only 2.
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