The alkali metals are a group ( column ) in the periodic table consisting of the chemical elements lithium ( Li ) , sodium ( Na ) , potassium ( K ) , rubidium ( Rb ) , caesium ( Cs ) , and francium ( Fr ) .
The alkali metals are lithium ( Li ) , sodium ( Na ) , potassium ( K ) , rubidium ( Rb ) , caesium ( sometimes written `` cesium '' , although `` caesium '' is preferred ) ( Cs ) , and francium ( Fr ) .