Question

what do the green - colored blocks indicate? alkali metals halogens alkaline metals noble gases

Explanation:

In the periodic table, alkaline - earth metals are in the second group. The green - colored blocks represent the elements in the second group of the periodic table which are alkaline earth metals. Alkali metals are in the first group, halogens in the 17th group, and noble gases in the 18th group.

Answer:

alkaline metals