Phosphorous is not found in its elemental form in nature. It is commonly found in a combination with other elements within the earth’s crust, as well as in plants, animals and rocks.
Phosphorus is an essential living element for plants (Fig 1.3), animals and even humans. These living organisms need phosphorus to build bones and teeth, these organisms also use it to build their cells and to build and store energy. There are about 700g of phosphorous in a typical 65 kg person and around 80 percent of this phosphorus is stored in the bones and teeth. Phosphorous is an important mineral in our diet, foods such as cheese, eggs, bread and meat are great sources of phosphorous.
Phosphorous is also a factor in DNA and RNA, as the chemicals are able to carry genetic information in cells. The main uses of Phosphorous is in matches and in bombs designed to set their targets on fire. Phosphorous mixtures are generally used in fertilizers, detergents and toothpastes. Some of these mixtures are then used to kill harmful insects.
There are about ten different forms of the element, but they fall into three main major categories; white, red and black.
White phosphorous is by far the more chemically reactive one out of the three. It is best if it is kept underwater. It easily combines with most elements and it can ignite freely upon exposure to air, letting off white fumes. It is extremely poisonous, and when exposed in sunlight it can turn into red phosphorus, which does neither glow or burn in air. Red phosphorus is not poisonous and it is found on the head of a match stick (Fig 1.5) the striking surface. Black Phosphorous has a flaky texture like graphite and is made by exposing white phosphorous to high pressure. It is also the least reactive form of phosphorous.
Phosphorus -32, is one of the many radioactive isotopes of Phosphorous. The nucleus of phosphorous -32 holds 15 protons and 17 neutrons. This is one extra neutron than the most common isotope of phosphorus i.e. Phosphorous -31. Phosphorus -32 only exists in small amounts on Earth, as it has a short half-life of 14.29
...(download the rest of the essay above)