Reactivity Series Flashcards
Define a metal
Metals are elements which lose electrons to form positive ions
Define a metallic bond
A metallic bond is the electrostatic forces of attraction formed between positive metal ions and a ‘sea’ of free-moving valence electrons
Why are alloys used over pure metals
- Alloys are harder and stronger
- Alloys do not corrode when reacting with oxygen and water
Define an alloy
An alloy is a mixture of a metal and one or more other elements
Name the reactivity series
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What are the properties of a metal ‘high up’ in the reactivity series
- Reacts quickly and vigorously
- Corrodes easily
- Loses electrons readily to form positive ions
Why are alloys harder and stronger than pure metals
- Atoms of added element have different size than atoms of pure metal
- This disrupts the orderly arrangement of atoms in pure metal
- Much harder for atoms to slide over one another without orderly arrangement of atoms
What are the properties of a metal ‘low down’ in the reactivity series
- React slowly
- Do not corrode easily
- Do not lose electrons readily to form positive ions
What is formed when a metal reacts with cold water
- Hydrogen gas
- Metal hydroxide
What is formed when a metal reacts with steam
- Hydrogen gas
- Metal oxide
Why does aluminium not react with water or steam
Aluminium is covered in a layer of non-porous aluminium oxide, which adheres strongly to the metal and prevents it from reacting
Which metals do not react with cold water or steam
- Aluminium
- Lead
- Copper
- Silver
- Gold
What forms when iron reacts with steam
- Hydrogen gas
- Iron (II,III) oxide (Fe3O4)
Why does aluminium not react at first with HCl, and what happens after
- Aluminium is covered in a layer of non-porous aluminium oxides, which adheres strongly to the metal and prevents it from reacting
- HCl will react with aluminium oxide to form water and soluble aluminium chloride
- Aluminium metal is exposed once oxide layer is washed away
- Reaction between acid and aluminium metal is rapid
Why does reaction between lead and HCl stop before completion
- Insoluble lead(II)chloride will form
- It will coat onto surface of lead metal and prevent further reaction between acid and metal
Give an example of a thermit reaction
A more reactive metal will displace a less reactive metal from its metal oxide
Reaction for decomposition of metal carbonates
Metal carbonate
–> Metal oxide + Carbon dioxide
Exception: Silver
What is a thermit reaction
A thermit reaction is when a great amount of heat is released during a reaction
Explain the displacement of metals from metal salt solution
A more reactive metal will displace a less reactive metal from its salt solution
Reaction for reduction with carbon
Metal oxide + Carbon
–> Metal + Carbon dioxide
Which metal carbonates cannot be decomposed by heat
- K2CO3
- Na2CO3
Reaction for reduction with hydrogen
Metal oxide + Hydrogen
–> Metal + Water
Which metal carbonates require very strong heating to decompose
- CaCO3
Which metal carbonates require moderate heating to decompose
- MgCO3
- ZnCO3
- FeCO3
- PbCO3
Which metal carbonates require gentle heating to decompose
- CuCO3
- Ag2CO3
What does silver carbonate decompose into
- Silver metal
- Oxygen
- Carbon dioxide
What are ores
Ores are compounds of metals mixed with large amounts of impurities
How does reactivity affect thermal stability of its carbonate
The more reactive the metal, the more thermally stable its carbonate is
What are the methods for extraction of metals
- Electrolysis
- Reduction of metal oxide with carbon
Which metals can only be extracted by electrolysis
- Potassium
- Sodium
- Calcium
- Magnesium
- Aluminium
Which metals are extracted by reduction of their metal oxides with carbon
- Zinc
- Iron
- Lead
- Copper
- Silver
What does it mean when gold is unreactive
Gold is found naturally uncombined in the ground as an element
Which metals are unreactive
Gold
How are very reactive metals extracted
- Always exist in compounds with strong chemical bonds
- Electrolysis is used to break down molten ionic compounds
How are moderately reactive metals extracted
- Found as oxides or sulfides
- Sulfides heated in air to form oxides
- Oxides reduced with carbon to form the metal and carbon dioxide
Define rusting
Rusting is the slow oxidation of iron to form hydrated iron(III)oxide in the presence of air and water
What is needed for rusting to occur
- Air
- Water
What can be added to increase the speed of rusting
- Sodium chloride
- Acidic substances
What are the main methods of rust prevention
- Protective layer
- Sacrificial metal
- Alloys
How to use a protective layer to prevent rusting
- Painting
- Oiling
- Plastic coating
- Chrome plating
How can a sacrificial metal prevent rusting
Galvanising (Zinc plating)
- Zinc, being more reactive than iron, loses electrons more readily than iron hence zinc corrodes in place of iron
How can using alloys prevent rusting
Stainless steel
