Question

which of the following combination of elements is the most reactive? (1 point) o ca and br o k and i o ce and i o na and br

Explanation:

Step1: Analyze the reactivity of metals

Metals in Group 1 (alkali metals) are highly reactive. Potassium (K) is in Group 1. Sodium (Na) is also in Group 1 but K is more reactive than Na as reactivity of alkali metals increases down the group. Calcium (Ca) is in Group 2 and cerium (Ce) is a lanthanide (less reactive compared to Group 1 metals).

Step2: Analyze the reactivity of non - metals

Halogens (Group 17 elements) are reactive non - metals. Bromine (Br) and iodine (I) are halogens. Reactivity of halogens decreases down the group, so Br is more reactive than I.

Since K (a very reactive metal) and Br (a relatively reactive non - metal) combination is considered. Na is less reactive than K among the given metal options.

Answer:

K and Br