What links soap, paper, heart disease and murder? Sodium. In the latest in our series of programmes looking at the world economy from the perspective of the elements of the periodic table, Justin Rowlatt returns to the chlor-alkali plant of Industrial Chemicals Ltd to discover from chemistry professor Andrea Sella how sodium is ripped from common table salt, and how it provides the grist for the global chemicals industry. One of its biggest uses is in the Kraft process, the most common way of pulping wood to make paper. Malcolm Brabant travels to a remote corner of Sweden, where the Munksjo paper company first put the technique into practice over a century ago. But sodium does not only digest wood - we hear the first-hand account of serial killer Leonarda Cianciulli on how she used caustic soda to dispose of her victims. Plus, Justin explores sodium's controversial role in our diet, and in regulating blood pressure. We pit Morton Satin, the self-styled 'Salt Guru' and spokesman for the US salt industry, against Graham MacGregor, a professor of cardiovascular medicine leading the drive to cut the salt content in food.

Chlorine is more than just a chemical used in swimming pools. This poisonous green gas is the great enabling element of the chemicals industry, used in creating your clothes, computer chips, medicines and flooring. Justin Rowlatt travels to Thurrock to tour the chlor-alkali plant of Industrial Chemicals Ltd with chief chemist David Compton, as he discovers the brutal process of extracting chlorine from the most mundane of raw materials - table salt. We hear from regular contributor Professor Andrea Sella of University College London who explains the many uses of chlorine. Finally Laurence Knight speaks to Mike Smith, an expert in the chlorine market from consultants IHS, about why the bursting of Spain's property bubble might put up the price of soap there.

Lithium is the electro-chemical element - big in batteries and bipolar disorder. Over two decades it has shot from obscurity to become almost synonymous with the way we power our gadgets. Presenter Justin Rowlatt hears from chemistry powerhouse professor Andrea Sella of University College London about what makes lithium so light and energetic. We hear from Gideon Long in Chile, who visits the world's richest source of lithium in the Atacama Desert, and about how neighbouring Bolivia believes it will dominate supply if demand for this alkali metal continues to see double-digit growth. Justin speaks to professor Nigel Brandon of Imperial College, an expert on cutting-edge battery research, about whether lithium can ever realistically hope to challenge a can of petrol as the best way to power a car. And, we hear from clinical psychologist Kay Redfield Jamison of Johns Hopkins University about the literally life-saving role lithium has played for sufferers of bipolar disorder - including herself. (Picture: Salar de Atacama; Credit: Gideon Long)

Neither rare nor earths, these 17 elements are nonetheless difficult and unpleasant to mine and refine. Chemically near-identical, these metals have unique magnetic and optical properties, making them essential in modern technology from fibre optics to wind turbines. So should we worry about China's stranglehold over their supply?

(Picture: 20 euro note glows under an ultraviolet light; Credit: Frans Dekkers/Thinkstock)

Diamonds are not forever. They can be burned, and these days they can be mass-produced in a factory. So can your jeweller tell the difference between a natural and chemically identical "fake"? And can the new breed of cheap, pure, manmade rocks be put to novel, hi-tech uses, beyond drilling rocks and adorning the wealthy?

Calcium is the great structural element. It is the basis of much of the great architecture in nature as well as many of the incredible structures made by man. Presenter Justin Rowlatt hears from chemistry supremo Andrea Sella at the Royal Institution in London, where calcium was first isolated two centuries ago. He visits the obscure birthplace of the biggest modern-day use of calcium - cement - and sees that use in action at London's giant Crossrail construction project. And, if that weren't enough, we also hear from Professor Serena Best of Cambridge University about how she is trying to replicate the way the human body uses calcium to construct bone.

Tin may seem old-fashioned, but it plays some surprisingly important roles in the modern economy. Presenter Justin Rowlatt meets our favourite chemist Andrea Sella of UCL at Pewters' Hall in London to discover the unique properties of the metal that sparked the Bronze Age.

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.

We all know carbon's role in global warming, but could element 6 also provide some solutions? Carbon fibre composites are making planes more fuel efficient, as Airbus explains. And wonder-material graphene has opened up a new world of applications, from energy storage to fuel filtration, as we discover at Manchester University.

Carbon is a great energy store – in plants and animals, but also as hydrocarbons – coal, oil and natural gas. From the Industrial Revolution onwards, burning these fossil fuels has released vast quantities of carbon dioxide into the air, affecting our climate and oceans. So can we ever get by without carbon-based energy?

Heavy and chemically inert, why is gold, of all the elements of the periodic table, so highly valued by mankind? Does it even provide a sound basis for modern currencies? What is it actually useful for? And, given its value, what extraordinary lengths will people go to, to recover every tiny scrap of it?