Question

which element is more reactive than rubidium (rb)?
a. aluminum (al)
b. cesium (cs)
c. strontium (sr)
d. beryllium (be)

Explanation:

To determine which element is more reactive than rubidium (Rb), we use the periodic table trends for reactivity of metals. For alkali metals (Group 1), reactivity increases down the group. Rubidium (Rb) is in Group 1. Cesium (Cs) is also in Group 1 and is below Rb in the periodic table. Aluminum (Al) is a post - transition metal, strontium (Sr) is an alkaline earth metal (Group 2), and beryllium (Be) is also an alkaline earth metal. The reactivity of alkali metals increases down the group, so Cs is more reactive than Rb. Aluminum, strontium, and beryllium are less reactive than Rb.

Answer:

B. cesium (Cs)