The boxes show four Group I metals in the order they appear down the group, following the arrow. What happens to their reactivity in this direction?
Question 1 Report
The boxes show four Group I metals in the order they appear down the group, following the arrow. What happens to their reactivity in this direction?
Answer Details
The arrow points down Group I through lithium, sodium, potassium and rubidium, and along that direction reactivity increases. Rubidium reacts violently with cold water while lithium fizzes gently.
Each step down adds an occupied electron shell, so the single outer electron lies further from the nucleus and is screened from it by more inner shells. The electrostatic attraction on that electron is weaker, so it is removed more easily and the 1+ ion forms more readily. Since losing that electron is what these metals do when they react, easier loss means greater reactivity:
\[ \mathrm{2K + 2H_2O \rightarrow 2KOH + H_2} \]
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