50 Fun Facts About Nitrogen

What is nitrogen's atomic number?

Its symbol is N and it heads group 15 of the periodic table.

Roughly what percentage of Earth's atmosphere is nitrogen?

Oxygen is about 21% and argon just under 1%.

What is the name for the group of elements headed by nitrogen?

The name comes from the Greek for 'to choke', a nod to nitrogen's asphyxiating nature.

Which Scottish physician is credited with discovering nitrogen in 1772?

He called it 'noxious air' and distinguished it from Black's 'fixed air', carbon dioxide.

What later career did nitrogen's discoverer pursue at the University of Edinburgh?

He was also Regius Keeper of the Royal Botanic Garden Edinburgh from 1786 to 1819.

What name did Lavoisier propose for nitrogen, meaning 'no life' in Greek?

It survives in French and other languages and in English words like azide and hydrazine.

Which French chemist coined the word 'nitrogène' in 1790?

He meant the element that 'begets nitre', since nitrogen was found in nitric acid and nitrates.

What does the German name for nitrogen, Stickstoff, refer to?

Ersticken means to suffocate; Dutch stikstof carries the same idea.

How many bonds hold the two atoms of an N2 molecule together?

The triple bond is among the strongest in any diatomic molecule.

Which diatomic molecule has the only bond stronger than nitrogen's triple bond?

That strength is why converting N2 into useful compounds is so hard for both organisms and industry.

At roughly what temperature does nitrogen boil at atmospheric pressure?

It freezes at about -210 °C, and the liquid has about 81% the density of water.

How many stable isotopes does nitrogen have?

Nitrogen-14 makes up 99.634% of the natural element; nitrogen-15 the rest.

Which isotope is the dominant radionuclide in the coolant of a pressurised water reactor?

It has a seven-second half-life and its gamma rays are the main way coolant leaks are detected.

Which isotope, with a ten-minute half-life, is used in PET scanning?

It must be made on site in a cyclotron by bombarding oxygen-16 with protons.

Which physicist discovered monatomic 'active nitrogen' in an electrical discharge in 1910?

His whirling cloud of brilliant yellow light reacted with mercury to form explosive mercury nitride.

Nitrogen ranks where among the most abundant elements in the human body by mass?

The body is about 3% nitrogen by mass, mostly in proteins and nucleic acids.

Which two chemists named the industrial process that turns air nitrogen into ammonia?

It uses finely divided iron as a catalyst and now underpins a huge share of the world's food supply.

In which year did Haber and Le Rossignol first make ammonia from air, drop by drop?

Their apparatus produced about 125 millilitres an hour.

Which company's Oppau plant first made Haber-process ammonia industrially in 1913?

Output reached 20 tonnes a day by 1914, just in time for the First World War's demand for nitrates.

In what year was Fritz Haber awarded the Nobel Prize in Chemistry for ammonia synthesis?

He actually received it in 1919; Carl Bosch got his in 1931 for high-pressure chemistry.

With whom did Carl Bosch share the 1931 Nobel Prize in Chemistry?

The prize honoured the introduction of high-pressure methods in chemistry.

Roughly what share of world food production relied on Haber-process fertiliser by 2010?

Industrial fixation eased a shortage that had rested on mined nitrates and guano.

Which 1902 method turns ammonia into nitric acid for fertilisers and explosives?

It made large-scale nitrate production possible for munitions in both World Wars.

Which enzymes let bacteria fix nitrogen from the air?

Lightning fixes some nitrogen too, but diazotrophic bacteria do most of the natural work.

Rhizobia bacteria fix nitrogen inside the root nodules of which plant family?

They cannot fix nitrogen without a plant host, which is why peas and clover enrich soil.

What is the main nitrogen-bearing waste that animals excrete after metabolising protein?

Breaking down nucleic acids yields uric acid as well.

Which two nitrogen amines give decaying flesh its characteristic smell?

They come from the breakdown of the amino acids ornithine and lysine.

What is nitrous oxide better known as?

It is made by heating molten ammonium nitrate to about 250 °C.

Which chemist coined the popular nickname for nitrous oxide?

Another 44 years passed before doctors tried it for anaesthesia; dentist Horace Wells did so in 1844.

What everyday kitchen product uses nitrous oxide as a propellant?

It carries the E number E942 as a food additive.

Which Italian chemist first synthesised nitroglycerin in 1846?

He called it pyroglycerin and warned against using it; Nobel later tamed it into dynamite.

Since 1878, nitroglycerin has been used as a medicine to treat what?

It works as a vasodilator, releasing nitric oxide in the body.

What was TNT originally used as after its synthesis in 1863?

Its explosive potential went unrecognised for three decades because it was so insensitive.

Which war of 1879-84 was fought over South American nitrate deposits?

Chile won the Atacama nitrate fields from Peru and Bolivia.

From which language does the word 'guano', for nitrogen-rich seabird dung, come?

Andean people had long gathered it from islands off the Peruvian coast as fertiliser.

Which explorer investigated guano's fertilising power at Callao, Peru, in 1802?

His writings made guano famous in Europe and set off a 19th-century trade boom.

Below roughly what depth does breathing air cause nitrogen narcosis in scuba divers?

At partial pressures above about 4 bar nitrogen acts as an anaesthetic.

Under 'Martini's law', one martini of narcosis equals how many metres of depth below 20 m?

It is a rough rule of thumb, not a physiological law; the effect is also called raptures of the deep.

Nitrogen coming out of solution in the blood on rapid ascent causes which condition?

Known as the bends, it can also strike astronauts who depressurise too fast.

What is the small nitrogen capsule that lets stout be sold in cans called?

Nitrogen's smaller bubbles make dispensed beer smoother and headier than CO2 alone.

Nitrogen gas from the decomposition of which compound inflates car airbags?

The same rapid gas release from nitrogen compounds powers many explosives.

What E number is pure nitrogen given as a food-packaging additive in the EU?

About two thirds of commercial nitrogen is used as an inert gas for jobs like keeping food fresh.

What phenomenon briefly protects skin from liquid nitrogen for about a second?

A layer of vapour insulates the skin, but longer contact causes cold burns.

What happened to an English woman in 2012 after drinking a liquid-nitrogen cocktail?

Liquid nitrogen expands 694 times on vaporising at room temperature.

Who in January 2024 became the first person executed by nitrogen asphyxiation?

Some US jurisdictions had adopted it as a substitute for lethal injection.

Which moon of Saturn has a dense atmosphere made mainly of nitrogen and methane?

It is the only moon known to have an atmosphere denser than Earth's.

On which dwarf planet and Neptunian moon does solid nitrogen form glaciers and geysers?

Even at those temperatures nitrogen ice is volatile enough to sublime into a thin atmosphere.

Which are the only two stable elements with which nitrogen forms no compounds?

With almost everything else it makes nitrides, from salt-like Li3N to hard interstitial metal nitrides.

What did the Scottish physician who isolated nitrogen in 1772 call the gas?

He distinguished it from Joseph Black's 'fixed air' (carbon dioxide) but did not recognise it as a wholly new substance.

Which chemist lost three fingers and an eye to nitrogen trichloride after first making it in 1811?

The dense, volatile liquid is easily set off; as a dilute gas it is tame enough to have been used to bleach flour.