Alkali metals

The most reactive metals - reactivity increases from Li to Fr
Due of the reactivity, they are stored under kerosene
In the valence shell they have only one electron, which makes them strong reducing agents
In nature they exist only in compounds
Soft, lightweight, shiny metals
All of them are good conductors of electricity and heat
They have very low melting points


Lithium
On air it burns crimson red flame
Compound with chloride is in devices for air conditioning
Lithium batteries and rechargeable batteries are used in electric motors
Lithium hydroxide is used to absorb CO₂ from the stale air in submarines and spaceships


Sodium
It is a biogenic element - found in all cells of plant and animal tissues
On air it burns orange yellow flame
Sodium hydrogen carbonate = Sodium bicarbonate is part of baking powder
In the nuclear industry and in aircraft engines is used as a material for dissipate heat
Sodium peroxide is applied in washing powders


Potassium
Well represented on Earth and in space
Its compounds are in seawater
Saltpeter = Potassium nitrate is used in the production of fertilizers and explosives
Potassium hydroxide is used in liquid soaps, medicines, artificial silk


Rubidium
Soft as wax
It is used in photocells serving for the direct conversion of light energy into electrical
Rubidium salts are added to a mixture of pyrotechnics and lighting effects are dyed to purple


Cesium
It is used in photocells, to construct power tubes, in night vision devices, television receivers


Francium
The heaviest chemical element of alkali metals