Question

15
select the correct answer.
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 trend of reactivity for alkali metals (Group 1) and alkaline earth metals (Group 2). Reactivity of alkali metals increases down the group. Rubidium (Rb) is in Group 1, Period 5. Cesium (Cs) is also in Group 1, Period 6, which is below Rb, so Cs is more reactive than Rb. 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. Alkaline earth metals are less reactive than alkali metals of the same period, and even down the group, the reactivity increase in Group 1 is more significant. So among the options, cesium (Cs) is more reactive than Rb.

Answer:

B. cesium (Cs)