Reactivity Series Flashcards
What do atoms form when they get rid of electrons in their outer shell?
Positive ions
Metals that form ions most easily are …
The most reactive
Metal + acid —> …
Metal + acid —> salt + hydrogen gas
Potassium + acid —> …
Potassium + acid —> potassium chloride + hydrogen (lots)
How does potassium react with acid?
Explosively
Possibly catching fire
Whizzing around
What do the most reactive metals produce the most of?
Heat
How to make a fair test reacting metals with acid
Each metal has the same mass and surface area
Use the same type and concentration of acid each time
Magnesium and cold acid observations
Fast reaction
Lots of fizzing
Tube gets hot
Metal dissolves
Iron and cold acid observations
Bubbles form on surface
Slow fizzing when warmed
Iron and warm acid observations
Slow fizzing
Iron very slowly dissolves
Aluminium and cold acid observations
Initially no reaction (protected by layer of aluminium oxide)
Aluminium and warm acid observations
Fast reaction
Lots of bubbles
Aluminium dissolves
Tube heats up
Copper and cold acid observations
No change
Dipper and warm acid observations
No change
Zion and cold acid observations
Slow fizzing
Metal dissolves
Tube gets warm
Lead and cold acid observations
No change
Lead and warm acid observations
No change
Magnesium + hydrochloric acid —> …
Magnesium + hydrochloric acid —> magnesium chloride + hydrogen
Order of reactivity
Potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
Zinc
Iron
Copper
Silver
Gold
What is a reactive metal?
Metals which like to combine with other elements to form compounds
Unreactive elements tend to remain as elements
Metal + water —> …
Metal + water —> metal hydroxides + hydrogen (gas)
Potassium reaction with water
Moves on the surface
Ignites and burns with a lilac flame
Fizzes and dissolves
Calcium reaction with water
Fizzes
Sinks then rises
Forms a cloudy solution
Magnesium reaction with water
Very slow reaction
May form bubbles over time
Magnesium reaction with steam
Reacts rapidly
Aluminium, zinc, iron reaction with steam
React slowly
Copper, silver, gold reaction with cold water
No reaction
Sodium + water —> …
Sodium + water —> sodium hydroxide + hydrogen
Zinc + steam —> …
Zinc + steam —> zinc oxide + hydrogen
Sodium and water reaction
Floats
Fizzes
Moves
May catch fire
If universal indicator is added to water and then sodium is added, what colour will the indicator turn?
Purple/violet
Lithium reaction with water
Floats
Fizzes
Moves
Dissolves
How do we test for hydrogen gas?
Hold a burning splint near the test tube with the gas
—> if hydrogen is present it will burn with a squeaky pop
Iron + copper oxide —>
Iron + copper oxide —> iron oxide + copper
Iron + copper oxide —> iron oxide + copper (explain)
Iron is the more reactive metal and it displaces the copper from its oxide
Iron gains oxygen (oxidised)
Copper loses oxygen (reduced)
Iron = reducing agent (causes copper to be reduced)
Copper = oxidising agent (causes iron to be oxidised)
What happens if you react magnesium with copper oxide?
A rapid and violent reaction
—> a bronze coloured metal (copper) and white powder (magnesium oxide) were formed
Magnesium + copper oxide —> magnesium oxide + copper
Magnesium is the more reactive metal and it displaces the copper from its oxide
Magnesium = oxidised, reducing agent
Copper = reduced, oxidising agent
When is a metal oxidised?
When it combines with oxygen
Or when it’s atoms lose electrons
When is a metal reduced?
When combined oxygen is removed
Or when its atoms gain extra electrons
How to remember oxidising and reducing
O xidation
I s
L oss
R eduction
I s
G ain
What is a redox reaction?
When one metal is oxidised and another is reduced
—> displacement reactions are all redox reactions
What is an oxidising agent?
A substance which causes another substance to be oxidised
E.g. by providing oxygen
What is a reducing agent?
A substance which causes another substance to be reduced
E.g. by removing oxygen
What is a displacement reaction?
A more reactive metal displacing a less reactive metal from a compound
What do ionic equations only show?
The particles that take part in the reaction - and change in some way
In ionic equations what is the name for the particles that don’t change?
Spectator ions
What is the order of reactivity of metal sulfates?
It is opposite to the order of reactivity of the metal elements
—> because a reactive metal does not easily let go of the elements it has combined with
Zinc + copper sulfate —>
Zinc + copper sulfate —> zinc sulfate + copper
What two substances are needed to make iron rust?
Water
Oxygen
What is the chemical name for rust?
Hydrated iron (III) oxide
What makes iron rust more quickly?
If the water is salty
When does iron not rust?
If it is in electrical contact with a more reaction metal
E.g. magnesium
What is corrosion?
Only the surface of a metal that dissolves
—> only the surface is exposed to substances in the environment
—> water, oxygen
Iron rusting:
The rust that forms at the surface gradually flakes off, revealing new metal underneath
—> the next layer can also rust and also flake away
Aluminium corroding:
Only the surface atoms are affected because when the top layer of aluminium atoms are oxidised to form aluminium oxide they form a protective layer around the rest of the metal
What are examples of creating a barrier against air or oxygen to stop iron rusting?
Paint
Oil or grease
Plastic
Electroplating
What is electroplating?
Using electrolysis to cover the iron in a thin layer of another metal
Why is creating a barrier only temporary to stop iron from rusting?
As soon as there is a hole in the coating, the iron will start to rust
What is sacrificial protection (stopping iron from rusting)?
Attaching a more reactive metal to the iron object
—> doesn’t need to fully cover the iron, only needs to be attached
If the object is exposed to oxygen and water the more reactive metal will be oxidised instead
What are examples of a sacrificial metal which could be attached to the underside of a ship to prevent it from rusting?
Zinc
Magnesium
What is galvanising (stopping iron from rusting)?
Coating the iron object in a thin layer of zinc (barrier method)
Even if the iron becomes exposed the zinc will react with the oxygen
—> zinc is more reactive than iron (sacrificial method)
- after time it will wear away and eventually iron underneath would start to rust
—> protection would last longer if the galvanised iron is also painted
—> provides an additional barrier protection
What is a halide?
A compound containing a halogen combined with a metal
