Aluminium (Al)
“Once dearer than gold and served only at emperors’ tables — today it wraps your breakfast, carries your current and frames your windows.”
How its electrons are arranged
Computed from the aufbau principle, with known real-world exceptions applied automatically.
Characteristics
- Configuration 1s² 2s² 2p⁶ 3s² 3p¹ — three valence electrons, so aluminium is a Period 3, Group 13, p-block metal that reacts as the Al³⁺ ion.
- The most abundant metal in the Earth’s crust, about 8% by mass — yet no nuggets exist, for it is always locked into oxides, clays and feldspars.
- Corrosion-proof by chemistry: bare aluminium grows an invisible film of Al₂O₃ within moments in air, sealing itself against water and weather.
- A superb conductor of electricity for its weight — which is why the cables swinging between village poles are aluminium with a steel spine.
A silvery-white, lightweight metal — soft enough to be rolled into paper-thin foil, yet tough enough for ladders, pots and window frames. Polished, it is a superb reflector of light, and a thumb-sized lump can be beaten into a sheet thinner than this page.
Where you meet it
✦ Uses
- Kitchen foil and cooking pots — the everyday aluminium kitchen of a Bangladeshi home; foil keeps bread, biryani and parathas warm and airtight.
- Overhead power lines — aluminium conductors with a steel core string Bangladesh’s rural electricity from pole to pole, chosen over copper for lightness and cost.
- Bodies of aeroplanes, buses and launches — at about one-third the density of steel, aluminium makes vehicles lighter and far cheaper to move.
- Drink cans, yoghurt-cup lids and blister packs — one thin, stamped sheet keeps food and tablets sealed away from air and light.
◍ Everyday examples
- The peel-off foil lid on a cup of sweet yoghurt and the silver paper wrapped around a bar of chocolate.
- The glinting wires atop concrete poles along a village road, humming through the afternoon.
- A window frame, a cooking pot and a can of soft drink — three aluminium faces of one Bengali household.
History & name
Dyers and tanners had prized alum — a double sulphate containing aluminium — for thousands of years without guessing a metal hid inside. In 1825 the Dane Hans Christian Ørsted prepared the first impure aluminium from aluminium chloride and potassium amalgam; two years on, Friedrich Wöhler refined the method and described the metal properly. Because extraction was so costly, aluminium sold above gold — Napoleon III of France honoured special guests with aluminium cutlery while ordinary diners managed with gold. Then, in 1886, 22-year-old Charles Martin Hall in Ohio and Paul Héroult in France, also in his twenties, independently found that electrolysing alumina dissolved in molten cryolite delivers cheap aluminium. Their Hall–Héroult process powers every smelter running today.