Final answer:
The Alkali Metals (Group 1) and Halogens (Group 17) contain the most active metals that are mostly found in compounds rather than in their pure form, owing to their high reactivity.
Step-by-step explanation:
The groups that contain metals so active they are mainly found in compounds, and rarely "pure", are the Alkali Metals (Group 1) and the Halogens (Group 17). Alkali metals such as lithium, sodium, potassium, rubidium, cesium, and francium, are highly reactive and typically occur in nature as part of various compounds. These metals are iconic for their reactivity with water and oxygen, forming alkaline solutions. On the other hand, halogens are the most reactive nonmetals and also primarily occur in compounds due to their high reactivity. Noble gases (Group 18), being the least reactive nonmetals, and transition metals (Groups 3-12) do not commonly form protective coatings and are not known for the same levels of reactivity as alkali metals and halogens.