Lithium
The mineral petalite, which contains lithium, was discovered by a Brazilian scientist named Jose Bonifacio towards the end of the 18th century. Then in 1817, lithium was discovered by Johan August Arfvedson, while he was analyzing petalite ore. Lithium was finally isolated by both William Brande and Humphry Davy. Since lithium has a very high reactivity it does not occur as the free metal in nature. However, large deposits of lithium in several rock forms are found in Nevada and California. Lithium is used in batteries, some grease, some glasses, ceramics, lubricants, and in medicine.
Sodium Sir Humphry Davy first isolated sodium in 1807. Sodium is never found as the free element in nature. However, sodium is the sixth most abundant element in the earth’s crust (2.6-3.0%) Sodium is essential to the human diet and it is important that sodium is replaced after sweating. Sodium is used to smooth the surface of some metals and is also used a heat transfer agent. Sodium vapor is used in lamps for street lighting. Also it is a key component in salt (sodium chloride)
Potassium In 1807 Sir Humphry Davy isolated potassium. Potassium metal is too reactive to be found isolated in nature however it is abundant. It makes up 1.5% of the earth’s crust. Potassium is mined in Germany and the USA. Potassium is essential to the human diet; however if it comes into contact with water it catches fire. Potassium metal is soft enough to be cut with a knife. Potassium is used in fertilizers, liquid detergent, and fireworks.
Rubidium Rubidium was discovered by Robert Bunsen and Gustav Kirchhoff in 1861.