- Alkali metals are a group of chemical elements in the first column of the periodic table. They are highly reactive metals that readily lose their outermost electron to form positive ions. The alkali metals are lithium, sodium, potassium, rubidium, cesium, and francium.
- Alkaline earth metals are a group of chemical elements in the second column of the periodic table. They are moderately reactive metals that readily lose their two outermost electrons to form positive ions. The alkaline earth metals are beryllium, magnesium, calcium, strontium, barium, and radium.
