K	Potassium By Jin 8th Grade Mill Valley Middle School	19
Properties Potassium is the seventh most strongest alkali metal and makes 1.5% weight of the earth's crust. It's an important element in the human diet. It oxidises very quickly in oxygen and has to be stored under aargon of a suitable mineral oil so it doesn't ignite in air/oxygen. So does all of the other alkali metals of the periodic table of elements. They decompose in water.	Uses The greatest demand for potassium is the use of fertilizers. It helps the plants grow in the soils. A combination alloy of sodium and potassium (NaK) is used as a heat transfer. They are also used for glass lenses, matches, salt peter, gunpowder, explosives, fire extinguishers, mercury batterty, dye, soap, and more.	History Potassium was discovered in 1807 by Sir Humphrey Davy. He obtained it from caustic potash. It was the first metal isolated by electrolysis. Sir Humphrey then soon invented the Davy Lamp to protect miners from the dangers of type of fire called the naked fire.
Table of Facts Atomic Number 19 Atomic Mass 3.91 Electrons/protons 19 Neutrons 20 Number of energy levels 4 (2,8,8,1) Melting Point 336.5 K Boiling Point 1038.7 K Period 4 Group 1(Alkali metal) Substance Solid/ Metal Color Silvery Origin of the name Potash Odor(less) Odorless		Explosibility Potassium can ignite in room temperature in oxygen It explodes with water, and when it explades with water, it becomes something called potassium hydroxide. Potassium fires have to be extinguished with a class D dry chemical extinguisher, sand, or with anything that clogs up oxygen. But don't use water to put it out or else it will ignite.
Glossary Oxidises: Aargon: Caustic Potash: Electrolysis:		Bibliography