Elemental

RNZ

To celebrate 150 years of the periodic table, get to know the back story of every element with our intrepid scientific hosts.

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98 episodes
Updated Dec 22, 2019

Episodes98

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Oct 22, 2019 · 11 min
Silver - a popular noble metal
Silver is widely used in jewellery, has interesting light sensitive abilities and has antimicrobial properties, says Prof Allan Blackman from AUT in ep 78 of Elemental. Argentina and the Rio de la Plata both take their name from the element silver, whose chemical symbol Ag comes from the Latin argentum. Silver has always played second fiddle to gold as it is not always found as a pure metal in nature. It is very prone to tarnishing, although that hasn't stopped its use in jewellery, cutlery and coins. Sterling silver is silver alloyed with copper to harden it. Silver salts used to be widely used in photography and they also have use in transition glass lenses which darken in the sun. While silver nanoparticles have antimicrobial activity, consuming too much silver for its supposed health benefits is not a good idea; United States political candidate Stan Jones has famously blue skin after many years of consuming home-made colloidal silver. This condition is known as argyria, says Professor Allan Blackman from the Auckland University of Technology, in episode 78 of Elemental. Go to this episode on rnz.co.nz for more details
Oct 20, 2019 · 10 min
Silicon - a ubiquitous part of modern life
Silicon is a blockbuster metalloid with many uses, from glass to computer chips & bathroom sealants, says Prof Allan Blackman from AUT in ep 77 of Elemental. Silicon underpins modern technology and has been a ubiquitous part of our lives since the 1950s, when the silicon chip was invented. But although billions of silicon chips are produced each year, this only uses 5 percent of the world's silicon production. The rest is used in glass, concrete, brick and silicone polymers. In nature the most abundant compounds of silicon are feldspars, which are aluminosilicate materials, and quartz or silica, better known as sand. In episode 77 of Elemental, Professor Allan Blackman from the Auckland University of Technology, introduces us silicates, silicones, silicas and many other permutations and uses of silicon. Go to this episode on rnz.co.nz for more details
Oct 17, 2019 · 8 min
Selenium - good reason to eat seafood & Brazil nuts
New Zealand soils lack the vital element selenium, which also used to be important in photocopiers and bathroom plumbing, says Prof Allan Blackman from AUT in ep 76 of Elemental. Selenium is named after the moon. There is some debate as to whether it is a metalloid or a non-metal. It is a trace element that New Zealand soils are deficient in. As a result, Kiwis are recommended to eat foods such as brazil nuts and seafood that are rich in selenium. Selenium occurs as three allotropes, and the grey allotrope has the unusual property of being an insulator in the dark but conducting electricity when it is exposed to light. This led to its extensive use in photocopies during the 1970s and 1980s, says Professor Allan Blackman from the Auckland University of Technology, in episode 76 of Elemental. Go to this episode on rnz.co.nz for more details
Oct 15, 2019 · 8 min
Scandium - the scandal of the scandium cricket bat
Predicted by Mendeleev & useful for alloying with aluminium, scandium was involved in a famous cricket scandal, says AUT's Allan Blackman in ep 75 of Elemental. Scandium is named after Scandinavia, and it was the second of Mendeleev's predicted elements to be discovered. Scandium is the first transition metal on the periodic table. It is roughly the same density as aluminium but has a higher melting point, which means it can be welded. The most famous story involving scandium concerns a cricket bat wielded by Dennis Lillee in a cricket test against England in 1979. The scandalised cricket authorities subsequently amended the Laws of Cricket to state that the blade of the bat must be made of wood, says Professor Allan Blackman from the Auckland University of Technology, in episode 75 of Elemental. Go to this episode on rnz.co.nz for more details
Oct 13, 2019 · 6 min
Samarium - magnets for making & listening to music
Samarium magnets are used in headphones & guitar pickups, and samarium was the first element named after a real person, says Prof Allan Blackman from AUT in ep 74 of Elemental. Samarium was the first element on the periodic table to be named after a real, as opposed to a mythical, person. It is a lanthanoid and alloys of it are useful in magnets, which can be thousands of times stronger than iron magnets. These magnets are found in headphones and high-end magnetic pickups for electric guitars and basses. Samarium magnets were also used in the motors of one of the earliest solar-powered electric aircraft, the Solar Challenger, says Professor Allan Blackman from the Auckland University of Technology, in episode 74 of Elemental. Go to this episode on rnz.co.nz for more details
Oct 10, 2019 · 8 min
Ruthenium - a 'sort of' precious metal
Ruthenium is a 'sort of' precious metal that is a useful catalyst and alloy. It is toxic and smells like ozone, says Allan Blackman from AUT in ep 73 of Elemental. Ruthenium is a rare transition metal produced mostly as a by-product of nickel mining. It is not widely used industrially, although it is found in some catalysts and alloys. It is more useful in the chemistry laboratory, where it has helped several chemists win Nobel Prizes. Ruthenium is toxic and if you have the bad fortune to be exposed to it, it smells of ozone says Professor Allan Blackman from the Auckland University of Technology, in episode 73 of Elemental. Go to this episode on rnz.co.nz for more details
Oct 6, 2019 · 9 min
Rubidium - expensive and not very useful
Rubidium is a reactive metal with few uses, named 'deepest red' due to its beautiful red spectral lines, says Allan Blackman from AUT in ep 72 of Elemental. Rubidium is named after the Latin word rubidius, meaning 'deepest red.' It is a group one metal, which makes it soft, highly reactive with water and with a low melting point. Rubidium helped win a Nobel Prize in Physics in 2001 for the discoverers of Bose-Einstein condensates, says Professor Allan Blackman from the Auckland University of Technology, in episode 72 of Elemental. Go to this episode on rnz.co.nz for more details
Oct 3, 2019 · 7 min
Rhodium - used in cars, drugs... and aftershave
Rhodium is an expensive precious metal that is used in catalytic convertors, to make the Parkinson's drug L-DOPA, create shiny jewellery and add the menthol taste to toothpaste, says Allan Blackman from AUT in ep 71 of Elemental. Rhodium is a very expensive precious metal, whose major use is in catalytic convertors, as it is very good at reducing levels of nitrogen oxides. The metal is used in mirrors and optical fibres, and as it is very shiny it is sometimes used as a coating for jewellery made from cheaper metals. Rhodium turns up in lip balm, cough remedies, toothpaste and aftershave, because rhodium catalysts are used to make synthetic menthol flavours, says Professor Allan Blackman from the Auckland University of Technology, in episode 71 of Elemental. Go to this episode on rnz.co.nz for more details
Oct 1, 2019 · 7 min
Rhenium - has a number of claims to chemical fame
Named after the Rhine river, rhenium is a metal with very high boiling and melting points, and it was the last naturally occuring, non-radioactive element to be discovered, says Prof Allan Blackman in ep 70 of Elemental. The chemical element rhenium is named after the Rhine River. It is one of the rarest elements in the earth's crust and the last of the naturally-occurring non-radioactive elements to be discovered. Rhenium has a number of claims to chemical fame: the metal has the highest boiling point (5596 degrees Celsius), third highest melting point and is the fourth most dense of all the elements. It finds use in alloys and catalysts, says Professor Allan Blackman from AUT, in episode 70 of Elemental. Go to this episode on rnz.co.nz for more details
Sep 29, 2019 · 9 min
Radon - radioactive basement risk
The radioactive gas radon can be a risk in the basements of stone houses and used to, erroneously, be touted for its health benefits, says Prof Allan Blackman from AUT in ep 69 of Elemental. Radon was originally named 'radium emanation' by its discoverer, Kiwi chemist Lord Ernest Rutherford. It is a noble gas and is produced by the radioactive decay of uranium and thorium. People who live in stone buildings can be at risk from radon gas as it escapes from rocks - it is heavy so it tends to lodge in the basements of houses. This is a problem in some parts of the United States, where you can buy radon detectors in supermarkets, but is not an issue in New Zealand. In the early twentieth century radon was touted as having health benefits before the dangers of radioactivity were recognised, says Professor Allan Blackman from the Auckland University of Technology in episode 69 of Elemental. Go to this episode on rnz.co.nz for more details
Sep 26, 2019 · 10 min
Radium - famous but not very useful
Radium was famously found by the Curies, and was once widely used in face creams, drinks and luminous watch dials, despite being highly radioactive, says Allan Blackman in ep 68 of Elemental. Radium was first isolated as an element from pitchblende by Marie and Pierre Curie in 1898, just two years after Henri Becquerel discovered radioactivity, although the dangers of radioactivity were not recognised at that time. Radium salts glow in the dark and were infamously used on luminous clock and watch dials in the early twentieth century. The workers who painted the dials, later known as the 'Radium Girls', were encouraged to lick the tips of their paint brushes and later successfully sued their employer when many of them began dying from cancer and radiation-induced illnesses. Radium was also added to water, coffee, beer and even face creams, before its dangers were realised. Radium is dangerous to humans because it behaves similarly in our bodies to calcium, says Professor Allan Blackman from the Auckland University of Technology in episode 68 of Elemental. Go to this episode on rnz.co.nz for more details
Sep 22, 2019 · 6 min
Protactinium - a very dull chemical element
Protactinium is a rare, radioactive element that has no uses and may be the most boring element, says Prof Allan Blackman from AUT in ep 67 of Elemental. Protactinium is rare, radioactive and one of the ten least abundant chemical elements in the Earth's crust. It was an element whose existence was predicted by Dmitri Mendeleev in the first periodic table in 1869, although it took 40 years for its existence to be confirmed. Little work was done on it until about 100 grams of the element were isolated in the early 1960s which allowed a small amount of research to be carried out. This may be the most boring chemical element, but Prof Allan Blackman from AUT suggests you listen to the 'Most boring chemical element' episode of Elemental to find out for certain. Go to this episode on rnz.co.nz for more details
Sep 19, 2019 · 11 min
Promethium - rare and unremarkable
Despite its gruesome mythical name, the radioactive element promethium has no particular claim to fame, says Prof Allan Blackman from AUT in ep 66 of Elemental. The element promethium is named for Prometheus, who stole fire from the Greek Gods and was gruesomely punished. The name was suggested by the wife of one of the Oak Ridge laboratory discovery team. Her reasoning was that the name reflects the power and peril of nuclear energy, by symbolising 'both the daring and the possible misuse of mankind's intellect.' All isotopes of promethium are highly radioactive and unstable with very short half-lives, so there is virtually none on earth. Promethium was used for a while in the Apollo Lunar Modules, in luminous paint used to illuminate some switches. However its glow ran out after just a couple of years so it was replaced with tritium-based paints, says Allan Blackman in episode 66 of Elemental. Go to this episode on rnz.co.nz for more details
Sep 15, 2019 · 6 min
Praseodymium - a long name but not many uses
Praseodymium is a metal wirh the second longest name on the periodic table and not many uses, says Prof Alan Blackman from AUT in ep 65 of Elemental. Praseodymium is the second-longest name on the periodic table. The prize for the longest element name goes to rutherfordium, named after the famous New Zealand physicist Lord Ernest Rutherford who won a Nobel Prize in chemistry. Praseodymium means 'green twin', a name that relates to confusion over the supposed element didymium. Didymium appeared on Mendeleev's original periodic table but turned out to be a mixture of elements, one of which was praseodymium. There are not many uses for this lanthanoid. It is used with neodymium in a form of glass known as didymium glass, that is used in welder's glasses. As well as protecting against light, it can be used to produce light such as searchlights, and it is used in magnets that have a role in wind turbines and hybrid cars. Go to this episode on rnz.co.nz for more details
Sep 12, 2019 · 11 min
Potassium - a matter of life and death
From levitating burnt buttocks, to excitable nerves and sure-to-rise baking, potassium is highly reactive and vital to life, says Prof Allan Blackman in ep 64 of Elemental. Potassium is a fundamental building block of life that pops up all over the place. The name comes from the English word potash, an old term for potassium salts obtained from wood ash. The chemical symbol K comes from kalium, an Arabic term for alkaline - or al-kali- plant ashes. Germanic countries went with the common name kalium for element 19 for many years. Potassium was discovered by the prolific element discoverer Humphrey Davy in 1807, who found it to be highly reactive with water. It also added a lovely violet colour to a flame, the same colour that is seen in the familiar potassium permanganate or Condy's crystals. Along with sodium, potassium is a critical part of the sodium-potassium pump, which is crucial for the transmission of nerve signals. Bananas are a good dietary source of potassium, which is an essential element. Industrially, most potassium is used in fertilisers as well as in soaps and detergents. Go to this episode on rnz.co.nz for more details
Sep 8, 2019 · 10 min
Polonium - few redeeming features
Polonium will be forever linked with the names Curie and Litvinenko and has negligible desirable features, says Prof Allan Blackman in ep 63 of Elemental. Polonium will be forever linked with the names Curie and Litvinenko and has negligible desirable features. Polonium (symbol Po and atomic number 84) is a radioactive metal, discovered by the Curies and named after Marie's home country of Poland, in 1898, a period when the country didn't actually exist. Po210 accumulates in tobacco and as a result cigarettes contain quite high levels of it, says Prof Allan Blackman, in ep 63 of Elemental. Go to this episode on rnz.co.nz for more details
Sep 5, 2019 · 9 min
Plutonium - nuclear bombs & nuclear power
A radioactive heavyweight associated with nuclear bombs & power, which is powering the Voyager spacecraft, says Prof Allan Blackman from AUT in ep 62 of Elemental. Plutonium is a radioactive heavyweight associated with nuclear bombs & power generation. It is mostly a synthetic element, although there are trace amounts in nature. Plutonium (symbol Pu, atomic number 94) was discovered and named in 1940 after the dwarf planet Pluto. Alternative names considered by the discovery team were 'ultimium' or ''extremium, because of the mistaken belief they had found the last possible element on the periodic table. Its discovery wasn't announced until the end of the second world war. The isotope 239Pu is a fissile isotope that has led to its use in nuclear reactions. 238Pu is powering the Voyager spacecrafts, which have left our solar system, says Prof Allan Blackman from AUT, in ep 62 of Elemental. Go to this episode on rnz.co.nz for more details
Sep 1, 2019 · 8 min
Platinum - another pricey precious metal
Platinum is useful in catalytic convertors, is used to treat testicular cancer and will be useful in hydrogen fuel cells, says Prof Allan Blackman from AUT in ep 61 of Elemental. Platinum is a rare precious metal, that doesn't corrode in oxygen. It occurs in its native state in nature and was used in burial goods by South Americans about 2000 years ago. Platinum is useful in catalytic convertors, along with palladium. It is used to treat testicular cancer and will be useful in hydrogen fuel cells, says Prof Allan Blackman from AUT, in ep 61 of Elemental. Go to this episode on rnz.co.nz for more details
Aug 29, 2019 · 14 min
Phosphorus - P was discovered in pee
Phosphorus, chemical symbol P, was first isolated as an element from thousands of litres of urine. Also found in guano, aka bird poo. Allan Blackman from AUT has the full story in ep 60 of Elemental. Phosphorus, from the Greek phosphoros meaning light-bearing, was the old name for Venus. It is the first element for which we know the exact year of discovery: 1669. Hennig Brand made 120 grams of phosphorus by boiling down 5,500 litres of urine, ending up with a waxy white solid that glowed in the dark without giving off heat. However, it wasn't recognised as an element until more than a century later. As well as white phosphorus, there are allotropes of red and black phosphorus. It is very flammable and was used in early matchsticks. Phosphates are important fertilisers, and one source of it is guano, aka bird poo. Allan Blackman from AUT has the full story, in ep 60 of Elemental. Go to this episode on rnz.co.nz for more details
Aug 25, 2019 · 12 min
Palladium - cleaning up your car's exhaust
Palladium is a pricey precious metal most commonly used in catalytic convertors on car exhausts, says AUT's Allan Blackman in ep 59 of Elemental. Palladium is a pricey precious metal that is one of a group of metals known as platinum group metals. Of these, palladium is the least dense and has the lowest melting point. It is named after the asteroid Pallas, which was discovered around the same time; Pallas was the Greek God of wisdom. White gold is alloyed with palladium. Palladium (symbol Pd, atomic number 46) is most commonly used in catalytic convertors on car exhausts, says AUT's Allan Blackman, in ep 59 of Elemental. Go to this episode on rnz.co.nz for more details