Describe the pattern in the reactivity of Group I elements.
State two observations you can make when potassium is added to water.
Write a chemical equation for potassium reacting with water.
Write a chemical equation for the reaction that happens when aqueous potassium iodide is added to chlorine.
State the final colour of the reaction mixture.
State the meaning of the term electrolysis.
State what must happen to sodium chloride before it can be electrolysed to produce sodium.
Write an ionic half-equation for the change that happens at the cathode during this electrolysis.
Use this information to give two properties of chromium that are different from those of Group I elements such as sodium.
Use this information to give two properties of chromium that are similar to those of Group I elements such as sodium.