Nitrogen (N)
“Nearly four of every five molecules you breathe are this famously lazy gas — yet it bursts into action in fertilizer sacks and chips packets.”
How its electrons are arranged
Computed from the aufbau principle, with known real-world exceptions applied automatically.
The notes
Characteristics
- The N≡N triple bond is the strongest single link between two like atoms in chemistry — breaking it costs so much energy that nitrogen neither burns, corrodes things, nor supports breathing.
- Agriculture’s standing paradox: crops stand bathed in nitrogen yet can starve for it, because no plant can split N₂ — only lightning, industrial reactors and certain soil bacteria can perform that trick.
- The configuration 1s² 2s² 2p³ gives nitrogen five valence electrons in a half-filled, extra-stable 2p shell — the reason it so reliably forms three bonds, as in ammonia (NH₃).
- Liquid nitrogen at −196 °C freezes whatever it touches into brittle, glass-like solids within seconds, wrapped in its own dramatic cloud of white mist.
A colourless, odourless, tasteless gas that makes up 78% of the air, always moving as N₂ molecules. The two atoms grip each other with a triple bond, the strongest bond between two like atoms, which is exactly why the gas is so strikingly unreactive. Chilled to −196 °C it condenses into a pale, mist-cloaked liquid that boils furiously at room temperature.
Where you meet it
✦ Uses
- Fertilizer: the Haber process welds nitrogen to hydrogen into ammonia, then urea — the blue sacks of urea Bangladeshi farmers carry into paddy fields are literally air, fixed into salt.
- Food packaging: chips and snack bags are flushed with dry nitrogen to crowd out oxygen and damp, which is why the packet stays puffed up and the crunch survives for months.
- Liquid nitrogen: snap-freezing food, blood and vaccines; freezing off warts in clinics; and show-stopping physics demonstrations at −196 °C.
- Inert blanketing: oil tankers, fuel tanks and transformer systems are topped with nitrogen to smother fires before they start; electronics plants use it as a clean, dry atmosphere.
◍ Everyday examples
- Every breath: about four of every five molecules you inhale are nitrogen, sailing through the lungs and straight back out, unchanged.
- The taut, pillow-like chips packet from a corner shop is inflated with pure nitrogen — squeeze it and you are feeling chemistry at work.
- A sack of urea at a fertilizer shop in Bangladesh — air itself, fixed and bagged, on its way to the paddy field.
History & name
In 1772 the Scottish physician Daniel Rutherford, still a student, removed the oxygen and the fixed air from a sealed pocket of atmosphere and was left with a gas that would neither feed a flame nor sustain a mouse — he called it “noxious air”. Scheele, Cavendish and Priestley were circling the same conclusion at the same time. Lavoisier, misled by the gas’s refusal to support life, named it azote, “the lifeless one” — French chemists still say azote today. The English name came in 1790 from Jean-Antoine Chaptal: nitrogen, “former of nitre”, after the saltpeter compounds the element builds.