1. Topic 11 Metals

2. Aim of lesson: Discuss the reaction of metals with: –Oxygen –Dilute Acid –Water Carry out a reaction to test the reactivity of metals with dilute acid.

3. Reaction of Metals When a metal reacts is loses electrons to form positive ions. e.g. Mg  Mg 2+ + 2e -  The metals atoms are oxidised. These reactions allow metals to be placed in a certain order  REACTIVITY SERIES Metals HIGH in the reactivity series are MORE reactive and so more readily form ions and compounds.

4. Reactivity Series Some metals are more reactive than others. The reactivity series places the most reactive metals at the top and the least reactive metals at the bottom. We can place metals in order of reactivity by comparing how well they react with other substances e.g. –Oxygen –Dilute acid –Water

5. Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Hydrogen Copper Mercury Silver Gold Platinum K Na Li Ca Mg Al Zn Fe Sn Pb H Cu Hg Ag Au Pt most reactive least reactive

6. Reacting Metals with Oxygen When metals are heated with air they may react with the oxygen present. Metal + Oxygen  Metal oxide Some metals react vigorously with oxygen and burn fiercely, some react more slowly and others do not react at all!

7. Experiment Aim: To investigate the reactions of magnesium and copper when burned in a plentiful supply of oxygen. Method: Potassium permangante Mineral wool Heat Magnesium or Copper Pyrex test tube

8. MetalObservation Magnesium Copper Conclusion: Magnesium is more reactive than copper. Results:

9. Metals reacting with oxygen

10. Formulae Equations Sodium + oxygensodium oxide Magnesium + oxygenmagnesium oxide Mg + O 2 22MgO Potassium + oxygenPotassium oxide Na + O 2 Na 2 O 2 4 K + O 2 K2OK2O 42

11. Reacting metals with dilute acid Some metals react with dilute acids to produce salts and hydrogen. Metal + Acid  Salt + Hydrogen

12. Experiment Aim: To investigate the reaction of different metals with acid. Method:

13. Results: Magnesium reacts vigorously with acid. Copper does not react with acid. Metals above hydrogen in the ECS react with acids to produced hydrogen gas, but metals below hydrogen do not react with acids. Metal + Acids  Salt + Hydrogen

14. Metals Reacting with Acid Magnesium + HCl Mg + HCl Potassium + HCl Potassium chloride + H 2 Magnesium chloride + H 2 MgCl 2 + H 2 K + HCl Aluminium + HClAluminium chloride + H 2 Al + HClAlCl 3 + H 2 2 KCl + H 2 222 3 1.5 63 Al + HClAlCl 3 + H 2 or

15. Reacting Metals with Water Some metals react with water and displace hydrogen to give an alkaline solution. Metal + Water  Metal hydroxide + hydrogen Again, some metals react more vigorously than others.

16. Potassium, sodium and lithium react so violently with water that they must be stored in oil, to prevent them reacting with moisture in the air!

17. Conclusion: –When metals react with water an alkali is produced. Hydrogen gas is also formed. Metal + Water  Metal Hydroxide + Hydrogen

18. Metals Reacting with water Lithium + H 2 O Li + H 2 O Sodium + H 2 O Sodium hydroxide + Hydrogen Lithium hydroxide + Hydrogen LiOH + H 2 Magnesium + H 2 O Mg + H 2 O 222 Na + H 2 ONaOH + H 2 222 Magnesium hydroxide + Hydrogen Mg(OH) 2 + H 2 2

19. Remember! Metal + Oxygen Metal oxide Metal + AcidSalt + Hydrogen Metal + Water Metal hydroxide + hydrogen

20. Quick Quiz 1.Where can the most reactive metals be found in the reactivity series? 2.What is produced when metals react with oxygen? 3.What is produced when metals react with acid? Most reactive metals at top, least reactive metals at the bottom. Metal oxide Salt and hydrogen