Potassium 40 radioactive dating
The alkali metals also include lithium, sodium, rubidium, cesium, and francium. Potassium is so active that it never occurs free in nature.It always occurs in compounds, combined with other elements.Potassium is a very light metal (the second least dense metal after lithium) and would float on water if it were not so reactive. Plants use it, for example, to make proteins, hence the greatest demand for potassium compounds is in fertilizers.
In electrolysis, an electric current is passed through a molten (melted) compound.
The electrical current breaks the compound into its elements.
It has become increasingly clear that these radiometric dating techniques agree with each other and as a whole, present a coherent picture in which the Earth was created a very long time ago.
Further evidence comes from the complete agreement between radiometric dates and other dating methods such as counting tree rings or glacier ice core layers.
Ar (argon), the atom typically remains trapped within the lattice because it is larger than the spaces between the other atoms in a mineral crystal.