alkali metals
Generally soft and silvery and very good conductors of heat and electricity; they are very reactant with nonmetals and break down in cold water.
francium 
The heaviest of the alkali metals is very rare and radioactive and has a very short life span (about 22 minutes).
cesium 
Rare metal that is used especially in photoelectric cells, atomic clocks, infrared lamps and treating certain cancers.
rubidium 
Metal similar to potassium but much rarer that is used in the manufacture of photoelectric cells and special kinds of glass and lasers.
potassium 
Very reactant light metal that is used especially in fertilizer and matches; its salts are used in medicine.
sodium 
Metal that is used especially in streetlights, kitchen salt (sodium chloride) and the manufacture of glass and cosmetic products.
lithium 
The lightest of all the metals is used especially in alloys for the aerospace industry, in household batteries and in medicine.