Question

comparing reactivity of different nonmetals
rank the nonmetals in each set from most reactive (1) to least reactive (3).
bromine:
chlorine:
iodine:

Explanation:

Step1: Recall halogen reactivity trend

Halogens (Br, Cl, I) reactivity decreases down the group. Cl is above Br, which is above I. So reactivity: Cl > Br > I.

Step2: Assign ranks (1=most, 3=least)

Most reactive: Chlorine (1). Then Bromine (2). Least reactive: Iodine (3).

Answer:

Bromine: 2
Chlorine: 1
Iodine: 3