Question

28 multiple choice 1 point select the most reactive element. mg cs sr na

Explanation:

Reactivity of metals increases down a group and decreases across a period in the periodic table. Cs (cesium) is in Group 1 (alkali metals) and is lower in the group compared to Na. Mg is in Group 2 and Sr is in Group 2 but Cs is more reactive among these as alkali - metals are more reactive than alkaline - earth metals and Cs is the most electropositive among them.

Answer:

B. Cs