K: Another highly reactive metal that readily forms bonds, just like Na. They both have one electron in their outermost energy level.
Li: Similar to Na and K, lithium is also a highly reactive metal that easily forms bonds. It has one electron in its outermost energy level as well.
Mg: Although not as reactive as Na or K, magnesium can still form bonds with other elements. Magnesium has two electrons in its outermost energy level.