Indium is a very soft metal, and as indium-tin-oxide it is an indispensable part of the swipeability of touchscreens, says Allan Blackman from AUT in ep 38 of Elemental.

If you use any kind of touch screen, whether smart phone or tablet, you have the element indium to thank.

ITO is indium oxide with a tiny amount of added tin. ITO conducts electricity, thanks to the tin, and it is transparent to visible light. These two features make it the perfect addition to the toughened glass screen of capacitive touch screens.

When you press your finger against the touch screen, an invisible grid of indium tin oxide senses the electrical disruption and this indicates where on the screen you have touched. It also enables you to swipe and pinch.

ITO won't be so useful in future, as it doesn't work with flexible touch screens.

Indium is also used in solar cells, says Professor Allan Blackman from AUT.

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Hydrogen is the first element on the periodic table. It is the oldest, lightest and most abundant element in the universe, but on earth it is usually found in compounds such as water, says AUT's Allan Blackman, in ep 37 of Elemental.

Hydrogen is the first element on the periodic table.

It is the oldest, lightest and most abundant element in the universe, but on earth it is usually found in compounds such as water.

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Holmium has interesting magnetic properties and is an important part of precise surgical lasers known as the 'Swiss Army knife' of lasers, according to Prof Allan Backman from AUT, in ep 36 of Elemental.

The obscure element holmium is a lanthanoid with interesting magnetic properties.

Named after the city of Stockholm (from Holmia, the Latin name for Stockholm) holmium finds use as a MRI magnet and in Ho:YAG lasers, which are homium-doped yttrium aluminium garnet lasers.

These precise surgical lasers have been described as the Swiss Army knife of lasers, says Professor Allan Blackman from AUT.

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Helium is the second most abundant element in the universe and possibly the most unreactive element on the periodic table, says Prof Allan Blackman from AUT, in ep 35 of Elemental.

Did you know that helium is so light, that all the gas from your helium balloons escapes gravity and ends up in space?

This is partly why it is rare on earth, but common in space, where it makes up 23 percent of the mass of observed matter in the universe.

And while a helium-infused squeaky voice can be the life and soul of the party, in most other respects it is an unremarkable element.

Odour? None.

Colour? None.

Taste? None.

Toxic? No.

Helium is possibly the most unreactive element on the periodic table - it doesn't even react with fluorine, the highly reactive Teflon element, says our resident expert Professor Allan Blackman from AUT.

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Hafnium is named after Copenhagen and as it has a very high melting point it was used in the thruster nozzles of the Apollo Lunar modules, according to Elemental's Allan Blackman from AUT.

Hafnium is named for Hafnia, the Latin name of Copenhagen.

Ceramics that contain the transition metal hafnium (atomic number 72, symbol Hf) are among the highest melting substances known.

The metal itself melts at 2230 degrees celsius, while hafnium carbide melts at 3200 degrees celsius. This makes it useful in plasma torches used to cut steel.

Professor Allan Blackman from AUT says that a niobium-hafnium-titanium alloy also has a high melting point, which is why it was used in the thruster nozzles of the Apollo Lunar Modules.

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Gold is highly valued for its colour as well as for being malleable and ductile, and as a noble metal it is unreactive and doesn't rust, says Allan Blackman from AUT in ep 33 of Elemental.

The name gold comes from the Anglo Saxon word gold, but its chemical symbol Au comes from the Latin word aurum, meaning 'glow of sunrise.'

Gold is the most malleable and ductile metal which is why it is beloved of jewellers. Its high value is a function of both its beauty and rarity.

It is very unreactive, and so chemically aloof that it bonds with only one element - tellurium.

The term 'acid test' is the use of nitric acid to determine whether a metallic object is gold - gold won't dissolve, but other metals such as silver will.

Nanogold will turn fibres like wool a lustrous purple colour, says Professor Allan Blackman from AUT.

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Germanium is a metalloid that was a key element in early transistors and is now used in optical fibres and infrared night vision scopes, says Allan Blackman from AUT in ep 32 of Elemental.

Germanium is a metalloid that was a key element in early transistors. The inventor of the first germanium-based transistors won a Nobel Prize.

It is now used in optical fibres and infrared night vision scopes.

Germanium (a metalloid with the atomic number 32) is named after Germany and was one of the elements whose existence on the periodic table was predicted by Dmitri Mendeleev.

As a semiconductor it has an initial low conductivity, which can be boosted by increasing the temperature or 'doping' it with other elements.

Professor Allan Blackman from AUT says that GeH4 is known as 'germane'.

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Gallium is the second element named after France, is a key element in mobile phones & Blu-ray players & melts at body temperature, says Prof Allan Blackman in ep 31 of Elemental.

Gallium is the second element on the periodic table named after France. It is a key element in mobile phones & Blu-ray players.

It looks like silver but melts at body temperature, a feature that fun-loving chemists used to exploit to play pranks on people, says Prof Allan Blackman from AUT. They would craft a spoon from gallium, which would dissolve when the unsuspecting user went to stir the sugar in their cup of tea.

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Gadolinium has interesting magnetic properties and is used as a contrast agent in MRI scans, according to AUT's Prof Allan Blackman in ep 30 of Elemental.

Gadolinium is named after the Finnish chemist Johannes Gadolin, who unfortunately didn't live to see the honour.

Gadolinium (atomic number 64, symbol Gd) is a lanthanoid and as is the case with that group of elements, it was difficult to isolate.

It has interesting magnetic properties and is used as a contrast agent in MRI scans, according to AUT's Prof Allan Blackman.

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Francium was the last naturally-occurring element to be discovered and has never been seen, says Prof Allan Blackman from AUT in ep 29 Elemental.

Francium was the last naturally-occurring element to be discovered.

It was found by French chemist Marguerite Perey in 1939, from an isotope of radioactive actinium. Marguerite had previously worked as a lab assistant with Marie Curie and became the first woman to be admitted to the French Academy of Sciences in 1962.

Francium and actinium share the title of 'rarest naturally occurring element.' Francium has never been seen, so there are many basic things about it that we don't understand.

Not surprisingly, says Professor Allan Blackman from AUT, it has no practical uses.

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