Wikijunior:The Elements/Phosphorus

What does it look, feel, taste, or smell like?
Phosphorus is white, purple, red, or black in color. When phosphorus is combined with certain other elements, it glows in the dark. Phosphorus can smell like garlic. It is not usually found free in nature.

How was it discovered?
Phosphorus was discovered by Hennig Brand in 1669 through experiments that involved boiling down and distilling the residue from urine.

Where did its name come from?
The name "phosphorus" comes from the combination of the Greek words "phos" (light) and "phoros" (bearer).

 Did You Know?
 * Plants need a small amount of phosphorus to live.
 * One type of phosphorus can be changed into another by increasing the temperature or the pressure.

Where is it found?
Elemental phosphorus comes in four forms: white phosphorus, red phosphorus, purple phosphorus, and black phosphorus. White phosphorus is very reactive and will spontaneously combust (burst into flames) when exposed to warm air. Therefore it is usually stored under water. The other forms are relatively nonreactive. One compound of phosphorus, calcium phosphate, is a major component of bones. Another, ATP, is used by cells to produce energy.

What are its uses?
Phosphorus is used in fertilizers and detergents. Phosphoric acid (H3PO4) is used to make soft drinks. Some phosphorus compounds are used to make light bulbs and television sets. Drinking water with phosphorus or taking phosphorus pills became fashionable and was thought to increase brain activity and make you smarter in the mid-1800s when phosphorus was discovered in the brain. In an ironic twist, phosphorus was used by the Allies in World War II to make their bombs glow bright during nighttime raids over Germany, the country of its initial discovery almost 300 years earlier. Phosphorus is also used to make nerve gas and inside glow sticks.

Is it dangerous?
White phosphorus is very toxic and is very damaging to human tissues, especially bones and cartilage. White phosphorus will spontaneously combust (burn) if exposed to air warmer than 35 degrees Celsius. Red, purple, and black phosphorus are relatively safe to handle.

Atom Information
The phosphorus atom (pictured right) shows a view of it very, very, zoomed in. At this level we can't even see light but if we magically could - this is more or less what we would see. In the centre is the nucleus (purple + red "subatomic particles") and around it are 3 electron "shells", the nucleus is made up of protons (red) and neutrons (purple). The protons have a little "+" sign on them because they carry positive charge, neutrons have no charge and electrons orbiting around the outside (blue) have a "-" sign because they have negative charge.

Ext: Electron Shells
On the 3 shells, the inner, middle, and outer, you can see varying amounts of electrons on the rings. On the inner ring, you can see two electrons.