Potassium, Sodium, Very vigorous, produces hydroxides and hydrogen Too reactive to add safely to acids Lithium gas Calcium Reacts gently and produces the same products as Can be added to very dilute acids but it’s – above going to be violent! Magnesium Reacts with to produce magnesium oxide and Reacts vigorously strongly exothermic – – hydrogen forms a salt and hydrogen Zinc or Iron Reacts slowly and forms an oxide and hydrogen Reacts slowly Anything Below No reaction No reaction Rusting of Iron This requires two things: Oxygen Preventing the Rusting of Iron (in iron oxidises into iron oxide Fe2O3) Using Barriers Keep water/oxygen away from the iron by painting, coating with oil…etc. Alloying the Iron Such as allowing it with chromium and nickel to produce stainless Sacrificial Anodes Galvanising iron by coating it with a layer of zinc. Zinc is more reactive than iron and will corrode instead. During the process it loses electrons to form ions. These electrons flow into the iron so any iron atom which has lost electrons immediately regains them. These means even if the zinc is scratched, the iron won’t rust. More on sacrificial anodes if the iron has already rusted, it can still be displaced by the more reactive zinc: – + 3Zn 2Fe + 3ZnO And this is the end. Good luck!
Potassium, Sodium, Lithium Very vigorous, produces hydroxides and hydrogen gas Too reactive to add safely to acids Calcium Reacts gently and produces the same products as above Can be added to very dilute acids – but it’s going to be violent! Magnesium Reacts with to produce magnesium oxide and hydrogen Reacts vigorously – strongly exothermic – forms a salt and hydrogen Zinc or Iron Reacts slowly and forms an oxide and hydrogen Reacts slowly Anything Below No reaction No reaction Rusting of Iron This requires two things: Oxygen Preventing the Rusting of Iron (in iron oxidises into iron oxide Fe2O3) Using Barriers Keep water/oxygen away from the iron by painting, coating with oil…etc. Alloying the Iron Such as allowing it with chromium and nickel to produce stainless Sacrificial Anodes Galvanising iron by coating it with a layer of zinc. Zinc is more reactive than iron and will corrode instead. During the process it loses electrons to form ions. These electrons flow into the iron so any iron atom which has lost electrons immediately regains them. These means even if the zinc is scratched, the iron won’t rust. More on sacrificial anodes – if the iron has already rusted, it can still be displaced by the more reactive zinc: + 3Zn 2Fe + 3ZnO And this is the end. Good luck!
the-ultimate-igcse-guide-to-chemistry-by-cgpwned.docx