Group 1 and group 17 reactivity trends

(i) Write the equation for the reaction of Rb with water, $\ce{H2O}$, including state symbols. (ii) Describe the type of bonding in $\ce{Rb}$ and in $\ce{H2O}$, and explain how the valence electrons in each produce that type of bond.

Which pair of elements reacts together most vigorously? A. Sodium and bromine B. Potassium and bromine C. Sodium and chlorine D. Potassium and chlorine

Which pair of elements would react together most vigorously? A. $\ce{Na(s)}$ and $\ce{I2(s)}$ B. $\ce{Cs(s)}$ and $\ce{I2(s)}$ C. $\ce{Na(s)}$ and $\ce{F2(g)}$ D. $\ce{Cs(s)}$ and $\ce{F2(g)}$

Sketch, on the axes, the graphs of the time for complete reaction against the mass of metal that you would expect for sodium and for potassium. Label each line.