The reactivity series
The reactivity series lists metals from the most to the least reactive. A metal can displace any metal below it from a solution of its salt.
The reactivity series
| Position | Metals | What it means |
|---|---|---|
| Most reactive | Potassium (K), sodium (Na), calcium (Ca), magnesium (Mg), aluminium (Al) | React with water or steam; never found free in nature |
| Middle | Zinc (Zn), iron (Fe), lead (Pb) | React with dilute acids; found as oxides, sulphides or carbonates |
| Hydrogen [H] | Not a metal, but used as a marker | Metals above it give hydrogen with dilute acids |
| Least reactive | Copper (Cu), mercury (Hg), silver (Ag), gold (Au) | Give no hydrogen with dilute acids; gold and silver are found free |
Activity: Zn, Fe, Cu and Al in salt solutions
- 1Clean strips of zinc, iron, copper and aluminium with sandpaper.
- 2Take solutions of zinc sulphate, ferrous sulphate, copper sulphate and aluminium sulphate in separate test tubes. Dip one metal strip in each.
- 3After 10 to 15 minutes, look for a coating on the strip or a change in the colour of the solution.
- 4★A metal that reacts is more reactive than the metal in the salt.
- 5Result: Al > Zn > Fe > Cu.Example: Zn(s) + FeSO₄(aq) → ZnSO₄(aq) + Fe(s)
★ key step
Results of the activity
| Metal | In aluminium sulphate | In zinc sulphate | In ferrous sulphate | In copper sulphate |
|---|---|---|---|---|
| Aluminium | Same metal | Reacts | Reacts | Reacts |
| Zinc | No reaction | Same metal | Reacts | Reacts |
| Iron | No reaction | No reaction | Same metal | Reacts: blue turns pale green |
| Copper | No reaction | No reaction | No reaction | Same metal |
Using the series
- Zinc displaces copper: Zn(s) + CuSO₄(aq) → ZnSO₄(aq) + Cu(s).
- Copper cannot displace iron, so copper in ferrous sulphate solution shows no change.
- Copper displaces silver, and the solution turns blue: Cu(s) + 2AgNO₃(aq) → Cu(NO₃)₂(aq) + 2Ag(s).
- Never store copper sulphate solution in an iron pot: iron would displace the copper and the pot would corrode.
Gold jewellery stays bright for generations, because gold is at the bottom of the series and hardly reacts. Iron gates and buckets, higher up, rust unless they are painted.
2 marks: “Can copper sulphate solution be stored in an iron vessel? Give a reason with an equation.” No. Iron is more reactive than copper and displaces it: Fe + CuSO₄ → FeSO₄ + Cu. The vessel would corrode and get holes.
3 marks: “Describe an activity to arrange zinc, iron, copper and aluminium in order of reactivity.” Dip each metal in solutions of the other three salts. Al displaces Zn, Fe and Cu; Zn displaces Fe and Cu; Fe displaces Cu; Cu displaces none. Order: Al > Zn > Fe > Cu.
"Please Stop Calling Me A Zebra, I Like Her Calling Me Sweet Girl": K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au.