reactivity of metals

• What do metals react with to produce metal oxides?


  Oxygen in the air
• What are oxidation and reduction reactions collectively called?

  Redox reactions
• What occurs during oxidation?


  Oxygen is added to an element or a compound
• What occurs during reduction?


  Oxygen is removed from an element or a compound
• What is the chemical equation for the reaction of copper with oxygen?

  2Cu + O ⟶ 2CuO
• In the reaction of copper with oxygen, what happens to copper metal?


  Copper metal is oxidised since oxygen has been added to it
• What is the chemical equation for the reaction of zinc oxide with carbon?

  ZnO + C ⟶ Zn + CO
• In the reaction of zinc oxide with carbon, what happens to zinc oxide?


  Zinc oxide is reduced since it has lost oxygen
• What happens to the carbon atom in the reaction of zinc oxide with carbon?


  The carbon atom is oxidised since it has gained oxygen
• What are redox reactions?


  • Simultaneous reactions of oxidation and reduction
  • Involve the addition or removal of oxygen
• What is the reactivity series of metals based on?


  How they react with other substances
• What do metal atoms form when they react with other substances?


  Positive ions by loss of electrons
• What does a higher position in the reactivity series indicate about a metal?


  The metal loses electrons easily and is more reactive
• Which non-metals are included in the reactivity series and why?


  Carbon and hydrogen, because they are useful in extracting metals from their oxides
• What is a mnemonic to remember the reactivity series of metals?


  “Please send lions, cats, monkeys and cute zebras into hot countries signed Gordon”
• What are the chemical properties of metals studied through?


  • Reactions with water
  • Reactions with dilute acids
• Which metals react with water?

  Metals above hydrogen in the reactivity series
• What do metals that react with cold water produce?


  A metal hydroxide and hydrogen gas
• What is the reaction of calcium with water?


  Ca + 2H₂O → Ca(OH)₂ + H₂
• How does magnesium react with cold water?


  Very slowly when finely divided
• What is the reaction of magnesium with gaseous water?

  Mg + H₂O → MgO + H₂
• What is the summary of metals reacting with cold water?

  • Potassium: Reacts violently
  • Sodium: Reacts quickly
  • Lithium: Reacts less strongly
  • Calcium: Reacts less strongly
  • Magnesium: Very slow reaction
  • Zinc, Iron, Copper: Generally unreactive
• What happens to metals in Group 1 and Group 2 when reacting with water?


  Group 1 metals are reactive, Group 2 metals are less reactive
• What do most metals react with?

  Dilute acids such as HCl
• What happens when acids and metals react?


  The hydrogen atom in the acid is replaced by the metal atom
• What is the general equation for the reaction of a metal with an acid?


  Metal + acid → metal salt + hydrogen
• What is the reaction of iron with hydrochloric acid?


  Fe + 2HCl → FeCl₂ + H₂
• What is the relationship between metal reactivity and ion formation?


  • More reactive metals become ions more easily
  • They lose electrons to form positive ions
• Why does aluminium not react with water or dilute acids despite being high in the reactivity series?


  It has a protective oxide layer that prevents reaction
• Why are carbon and hydrogen included in the reactivity series?


  They help predict how metals can be extracted from their ores
• What does it mean if a metal can displace hydrogen from water or acids?


  The metal is higher in the reactivity series than hydrogen
• What can carbon do in relation to metal oxides?


  Carbon can remove oxygen from metal oxide ores
• What happens to metals below carbon in the reactivity series?


  They can be extracted by heating the oxide with carbon
• What happens to metals higher than carbon in the reactivity series?


  They must be extracted by other methods, such as electrolysis
• What are displacement reactions in metals?


  • More reactive metals displace less reactive metals
  • Occur in reactions with metal oxides or aqueous solutions of metal compounds
• What is an example of a displacement reaction involving zinc and copper oxide?

  Zn + CuO → ZnO + Cu
• What is the thermite reaction?


  A highly exothermic reaction between iron(III) oxide and aluminium
• Why is the thermite reaction used in welding?


  It releases so much heat that the iron formed is molten
• What is the equation for the thermite reaction?


  Fe₂O₃ + 2Al → 2Fe + Al₂O₃
• What happens in displacement reactions between metals and aqueous solutions of metal salts?


  • More reactive metal displaces less reactive metal
  • The more reactive metal disappears from the solution