Where are the most reactive nonmetal elements found on the periodic table?

On the right side. periods 1 2 3 4 5 and 6 letters H, He, B, C, N, O, F, Ne, Si, P, S, Cl, Ar, Ge, As, Se, Br, Kr, Sb, Te, I, Xe, At, Rn,

Most reactive non-metals: the halogens in group 7 (at right of table)

More reactive as you go up group

Most reactive metals: the alkali metals in group 1 (at left of table). More reactive as you go down the group