**Physical Characteristics of Aluminium:** – Aluminium is a chemical element with symbol Al and atomic number 13. – It has a density lower than that of other common metals, about one-third that of steel. – Aluminium forms a protective layer of oxide on the surface when exposed to air. – It visually resembles silver and has a great ability to reflect light. – Aluminium is soft, nonmagnetic, and ductile. – Aluminium metal appears silvery white to dull gray. – Aluminium mirrors are highly reflective in the ultraviolet and infrared spectrum. – Anodizing aluminium adds a protective oxide layer to prevent wear. – The density of aluminium is 2.70g/cm^3, about one-third that of steel. **Isotopes and Electron Shell of Aluminium:** – Only Al-27 is stable among aluminium isotopes. – Al-27 is the only primordial aluminium isotope on Earth. – Aluminium has an electron configuration of Ne 3s^2 3p^1. – A free aluminium atom has a radius of 143pm. – Aluminium atoms form a face-centered cubic crystal system at standard temperature and pressure. – Aluminium can surrender its three outermost electrons in chemical reactions. – The electronegativity of aluminium is 1.61 (Pauling scale). **Properties of Aluminium – Mechanical, Thermal, Electrical, and Chemical:** – Pure aluminium yield strength: 7-11 MPa, while aluminium alloys have yield strengths of 200-600 MPa. – Aluminium is ductile with 50-70% percent elongation and malleable, easily drawn and extruded. – It is an excellent thermal and electrical conductor, around 60% conductivity of copper. – Aluminium is essentially unaffected by static magnetic fields. – Combines characteristics of pre- and post-transition metals. – High chemical affinity to oxygen and resists corrosion due to passivation. – Reacts with nonmetals upon heating. **Compounds and Derivatives of Aluminium:** – Majority of compounds feature aluminium in oxidation state 3+. – Almost all aluminium(III) compounds are colorless. – Aluminium hydrolysis forms a precipitate of aluminium hydroxide. – Aluminium trichloride has major industrial uses. – Compounds like AlR3 and AlR1.5 exist in organoaluminium compounds. – Aluminium trialkyls and triaryls are reactive and volatile. – Aluminium alloys well with most metals except alkali and group 13 metals. **History, Production, and Usage of Aluminium:** – First record of alum dates back to 5th century BCE by Greek historian Herodotus. – Industrial production of aluminium was established in 1856 by Henri Etienne Sainte-Claire Deville. – World production of aluminium exceeded 100,000 metric tons in 1916. – Aluminium surpassed copper in production in 1954, becoming the most produced non-ferrous metal. – China is the top producer of aluminium with a world share of 55%. – Recycling has become an important task in the aluminium industry, reducing energy consumption and waste.