Question

what do the red - colored blocks indicate? noble gases alkaline earth metals alkali metals non - metals

Explanation:

Noble gases are in Group 18 of the periodic table. Alkaline earth metals are in Group 2. Alkali metals are in Group 1. Non - metals are elements that lack metallic properties. Looking at the red - colored blocks, they include elements like He, Ne, Ar, etc. which are noble gases. Also, non - metals like C, N, O, F, P, S, Cl, Se, Br, I are also in the red - colored blocks.

Answer:

non - metals