30-Second Elements

Today, three quarters of a million tons of argon are extracted annually from liquefied air, because its very inertness makes it useful. You can fill light bulbs, fluorescent tubes and double-glazed windows with it, or use it as a propellant for aerosols, industrial sprays and even futuristic ion-propulsion spacecraft engines, without worrying that it will react or be toxic.

Like the other elements that share its column in the periodic table, it is an inert gas: unreactive, if not downright lazy (the quality for which it’s named). Argon does not lose or share any electrons by undergoing chemical reactions; it has a so-called filled shell of electrons.

Ramsay confirmed that these gases were, indeed, unique elements by examining the characteristic spectrum of light they produce when excited by an electric discharge. His co-worker, fellow British chemist Morris Travers, was thrilled to note a ‘blaze of crimson light’ in the case of neon.

The knowledge that iodine is relatively abundant in seawater and marine plants explained why sea sponges had proved to be an effective folk remedy for goitre before.

Chlorine’s dark side was first unleashed on 22 April 1915, when 6,000 cylinders along the German army’s front line were used against Algerian troops of the French army near Ypres. This terrifying weapon was the work of German chemist Fritz Haber. Chlorine burns away the lining of the lungs, leaving victims drowning in the fluid that oozes out.

Fluoride (F−) strengthens bones and teeth by converting the calcium phosphate of which they are made to a harder mineral, fluoroapatite.

The noble gases all have full outer shells of electrons and so do not readily form compounds. They are called ‘noble gases’ because they rarely react with other elements – a reference to members of the nobility who traditionally kept themselves aloof from other people in society.

inert A substance that does not undergo a chemical reaction. The ‘noble gases’ were at one time known as the inert gases.

We don’t see much plutonium on the earth because during the 4.5 billion years of the earth’s existence, almost all of our natural plutonium, with the longest half-life at around 80 million years for plutonium-244, has undergone radioactive decay to form uranium.

In 1938, German chemists Otto Hahn and Fritz Strassmann in Berlin – together with the Austrian physicist Lise Meitner – found that a uranium nucleus may split in half (undergo fission) when it absorbs a neutron, raising the possibility of a sustained uranium chain reaction that could liberate its nuclear energy more quickly. In a nuclear reactor, the chain reaction is controlled; in a bomb, it becomes a runaway process, releasing the nuclear energy in an explosion