Final answer:
The most reactive family of metals is the alkali metals, which include elements like lithium, sodium, and potassium. In contrast, the alkaline earth metals, which include elements like magnesium and calcium, are less reactive than alkali metals, though still quite reactive.
Step-by-step explanation:
The family of metals that is the most reactive is the alkali metals. Alkali metals include lithium, sodium, potassium, rubidium, cesium, and francium. They belong to group 1 of the periodic table and are known for their vigorous reactions with water. Comparatively, the alkaline earth metals are also reactive but less so than alkali metals. While radium is considered a part of the alkaline earth metals, it is highly radioactive and unstable.
The Alkaline Earth metals, such as beryllium, magnesium, calcium, strontium, barium, and radium, have higher first ionization energies than the alkali metals, making them less reactive. The alkaline earth metals form alkaline solutions when their oxides react with water and are common in deposits of limestone and other minerals. They are shiny, silvery-white and somewhat reactive, and readily lose their valence electrons to form compounds with an oxidation state of 2+, particularly in reactivity conducive environments.