Here's why:

* Electron Configuration: Alkali metals have one valence electron (electron in their outermost shell).

* Stability: They achieve a stable electron configuration, like the noble gases, by losing this single valence electron.

* Cations: Losing an electron results in a +1 charge, forming a cation.

Examples of alkali metals include:

* Lithium (Li)

* Sodium (Na)

* Potassium (K)

* Rubidium (Rb)

* Cesium (Cs)

* Francium (Fr)