Here's why:
* Valence electrons are the electrons in the outermost energy level of an atom, and they are the ones involved in chemical bonding.
* Groups on the periodic table are vertical columns, and elements within a group share similar chemical properties because they have the same number of valence electrons.
* Alkali metals (Group 1) have one valence electron.
Other groups have more valence electrons:
* Group 2 (Alkaline Earth Metals): Two valence electrons
* Groups 13-18: Have 3-8 valence electrons, respectively.
