The alkali metals are so called because they all react with water to give alkaline solutions, with a of 14.

All the reactions are similar, so they are put into a family called Group I.

They all have one shell electron which they can to get a noble gas structure. When the electron is lost, they form ions.

They are all metals, easily cut with a knife. They rapidly on exposure to air. They have relatively densities

The metals get more as you go down the group. Lithium is the least, the most.

There is another alkali metal called francium. It is very , with a half-life of 20 minutes.