fosforatom

Fosforatom, or phosphorus atom, is the chemical element with atomic number 15 and the symbol P. It belongs to group 15 (the pnictogens) in period 3 of the periodic table. Its electron configuration is [Ne] 3s2 3p3. Phosphorus is a non-metal and an essential element for living organisms, occurring in minerals such as apatite and in biological molecules like DNA, RNA, ATP, and phospholipids. The most abundant stable isotope is 31P; several radioactive isotopes have been produced for research and medicine.

Phosphorus exists in several allotropes. White phosphorus consists of P4 tetrahedra, is highly reactive, and glows faintly in the dark. It is toxic and stored under water to keep it from igniting. Red phosphorus, formed by heating white phosphorus in the absence of air, is less reactive and used in safety matches and flame retardants. Black or violet phosphorus is a more stable, layered form.

Natural phosphorus occurs mainly as phosphate minerals, notably apatite. Industrial production begins with mining phosphate rock, which is reduced with silica and coke in an electric arc furnace to yield elemental phosphorus, typically as P4. White phosphorus is then used to manufacture phosphoric acid (H3PO4), phosphate fertilizers, and various phosphorus compounds such as phosphorus oxides (e.g., P4O10).

Phosphorus exhibits oxidation states from -3 to +5. Its compounds include phosphates (PO4^3-), phosphoric acid, and phosphorus halides such as PCl3 and PCl5. In biology, phosphate groups store energy in ATP, form the backbone of DNA and RNA, and constitute cell membranes as phospholipids.

History: Hennig Brand discovered phosphorus in 1669 by distilling urine. The name derives from Greek phosphoros, "light-bearing", in reference to the element's glow in the dark.

Safety: White phosphorus is highly toxic and ignites in air; it is stored underwater and handled with care. Environmental and health concerns arise from phosphate mining and phosphorus-containing compounds.