Rank #1: Helium (He)
(Picture: US National Helium Reserve; Credit: Jonny Dymond/BBC)
Jul 12 2014
Rank #2: Aluminium (Al)
Jul 13 2014
Rank #3: Magnesium (Mg)
(Picture: Magnesium alloy flame test; Credit: Magnesium Elektron)
Sep 30 2015
Rank #4: Gallium & Indium (Ga, In)
Jun 03 2015
Rank #5: Iron (Fe) - the Industrial Revolution
Mar 18 2015
Rank #6: Technetium (Tc)
Mar 11 2015
Rank #7: Mercury (Hg)
(Picture: Ghanaian artisanal miner holds mercury in his hand; Credit: Matt Davies/BBC)
Jul 14 2014
Rank #8: Copper (Cu) - electricity
Jun 25 2015
Rank #9: Cobalt (Co)
Jul 22 2015
Rank #10: Lead (Pb)
Yet lead in petrol is also accused of having inflicted brain damage on an entire generation of children in the 1970s, as the economist Jessica Wolpaw-Reyes of Amherst College explains. And, producer Laurence Knight travels to one of the UK's only two lead smelters - HJ Enthoven's at Darley Dale in Derbyshire, the historical heartland of the UK lead industry - to see what becomes of the lead in your car battery. And, we speak to the director of the International Lead Association, Andy Bush.
Oct 01 2014
Rank #11: Beryllium (Be)
Image: A man holding a shockproof X-ray tube - Beryllium is used in the construction of these. Credit: Douglas Miller/Topical Press Agency/Getty Images
Oct 22 2015
Rank #12: Boron (B)
Jun 11 2015
Rank #13: Fluorine (F)
Mar 04 2015
Rank #14: Uranium (U)
He is given a tour of the operational power station, Sizewell B, which generates 3% of the UK's electricity, by EDF's head of safety Colin Tucker, before popping next-door to the original power station, Sizewell A, where he speaks to site director Tim Watkins about the drawn-out process of decommissioning and cleaning up the now-defunct reactors.
But while Sizewell remains reassuringly quiet, big explosions come at the end of the programme. We pit environmentalist and pro-nuclear convert Mark Lynas against German Green politician Hans-Josef Fell, the joint architect of Germany's big move towards wind and solar energy, at the expense of nuclear. Is nuclear a green option? It really depends whom you ask.
(Photo: Perdiodic table)
Oct 08 2014
Rank #15: Tin (Sn)
He discovers the metal's role in plastics and electronics, and visits the giant Pilkington glass factory to find out how tin revolutionised the glass-making industry. And he meets two very venerable tin chemists, Alwyn Davies and Ted Fletcher.
Jul 18 2014
Rank #16: Tungsten (W)
We get a tour of the SGS Carbide tool factory with managing director Alan Pearce, and we consider the market value of this very useful element with Mark Seddon, head of consultancy firm Tungsten Market Research.
Should we worry that China dominates demand? And why is it taking so long to open up new sources? We visit the Hemerdon mining project in the pretty English county of Devon, and hear from Russell Clark, head of the mining firm Wolf Minerals that is reopening it.
And, there is a very special reason why your government should care about its tungsten supplies, as military technology analyst Robert Kelley explains.
(Picture: Soldier lays armour-piercing sabot round on the ground during Operation Desert Shield; Credit: US Department of Defense)
Jul 29 2014
Rank #17: Titanium (Ti) - catalysts
Presenter Laurence Knight heads to the Ineos oil refinery in Grangemouth, Scotland, to see how just a smidge of a titanium-based catalyst transforms a type of natural gas into the stuff of food packaging, bottles and car bumpers.
He hears from Prof Andrea Sella why most of us spend our lives surrounded by titanium without even realising it.
And Brian Pickett of pigments manufacturer Cristal explains why his company has been painting various bits of London to further the fight against city smog.
(Picture: Window cleaner; Credit: Peter Parks/Getty Images)
Sep 16 2015
Rank #18: Rare Earth Elements (Ce, Nd, Dy, Er, etc)
(Picture: 20 euro note glows under an ultraviolet light; Credit: Frans Dekkers/Thinkstock)
Jul 21 2014
Rank #19: Lithium (Li)
Jul 22 2014
Rank #20: Carbon (C) - energy
Jul 16 2014