B. Elements in the same period have what in common? (Look at the table)

Water ionizes by the equation h2o(l)⇌h+(aq)+oh−(aq) the extent of the reaction is small in pure water and dilute aqueous solutions. this reaction creates the following relationship between [h+] and [oh−]: kw=[h+][oh−] keep in mind that, like all equilibrium constants, the value of kw changes with temperature.

Consider the reduction reactions and their equilibrium constants. cu+(aq)+e−↽−−⇀cu(s)pb2+(aq)+2e−↽−−⇀pb(s)fe3+(aq)+3e−↽−−⇀fe(=6.2×108=4.0×10−5=9.3×10−3 cu + ( aq ) + e − ↽ − − ⇀ cu ( s ) k =6.2× 10 8 pb 2 + ( aq ) +2 e − ↽ − − ⇀ pb ( s ) k =4.0× 10 − 5 fe 3 + ( aq ) +3 e − ↽ − − ⇀ fe ( s ) k =9.3× 10 − 3 arrange these ions from strongest to weakest oxidizing agent.

Analyze the reaction to determine whether the reaction is exothermic or endothermic. explain your reasoning.