Sodium is the 11th element on the periodic table. It is the 6th most abundant element on the earth. Sodium is a highly reactive element and is never found in nature. Sodium explodes when wet but after being combined with another element it is very useful. It can be made into titanium, gas for yellow stop lights, even common table salt.
Potassium is the 19th element of the periodic table. It is a highly reactive element, but is never found free in nature. It is sometimes used as heat transfer material usually in nuclear reactors. It also combines to make soaps and washing detergents. It also is used in fertilizers.
Rubidium is the 37th element on the periodic table. Usually found as a by product of lithium Uses of rubidium are still few, some believe it can be used as a propellant, and it may eventually be useful in batteries. It is also used in the timing mechanism of clocks.
Cesium is the 55th element on the periodic table. It has a limited use because it has the second lowest melting point of metallic elements. One major use is in atomic clocks. It is believed to one day that it may be used as a propellant.
Francium is the 87th element on the periodic table. Because of the little amount if this element there are no know uses of it except research.
