Metals Flashcards
What is metallic bonding?
Metallic bonding is the electrostatic force of attraction between positively charged ions and
delocalised (free to move) electrons.
Why are metallic elements conductors of electricity?
Metallic elements contain delocalised electrons.
What can metals react with?
Water, acid and oxygen.
List 5 metals that react with water, oxygen and acid.
- Potassium
- Sodium
- Lithium
- Calcium
- Magnesium
List 5 metals that react with water and acid.
- Aluminium
- Zinc
- Iron
- Tin
- Lead
List 2 metals that react with oxygen.
- Copper
2. Mercury
List 2 metals that do not react with water, acid or oxygen.
- Silver (This may react over a long period of time)
2. Gold
What products are made when a metal reacts with water?
Metal Hydroxide and Hydrogen
What products are made when a metal reacts with acid?
Metal Salt and Hydrogen
What products are formed when a metal reacts with oxygen?
Metal oxide
What happens when metals form ions?
They give away one or more of their outer electrons.
Give 2 examples of metals that lose their outer electrons easily?
Lithium and Sodium.
Give 2 examples of metals that DO NOT lose their outer electrons easily?
Silver and Gold
What is the electrochemical series?
A list of metals arranged in rank order of how easily the metal atoms lose electrons.
*This can be found in the SQA Data Booklet.
Which properties do metals have that make them useful? (4)
Strength
Malleability
Conduction of electricity
Conduction of heat.
What are metal ores?
Ores are naturally occurring rocks that contain metals or metal compounds in sufficient amounts to make it worthwhile extracting them.
What determines the method used to extract the metal from the ore?
Depends upon the reactivity of the metal and so how stable the ore is.
What happens when the metal ion in the compound gains electrons?
They are reduced.
How can metals of low reactivity be extracted?
By use of heat.
Give an example of an extraction of a metal with low reactivity.
Silver oxide → [heat] → silver and oxygen
Metals with low reactivity only need to be heated.
How can metals of medium reactivity be extracted?
By use of heat and carbon or carbon monoxide
Give an example of an extraction of a metal with medium reactivity.
Iron oxide → [carbon + heat] → iron + carbon dioxide.
How can metals of high reactivity be extracted?
By use of electrolysis.
Give an example of an extraction of a metal with high reactivity.
sodium ions → [electrons] → sodium metal
- This is a redox reaction.
What is electrolysis?
It is the decomposition of an ionic compound into its elements using electricity.
What two reactions happen in electrolysis?
Reduction
&
Oxidation
What is Reduction?
Reduction is when the positive metal is attracted to the negative electrode where it gains enough electrons to turn back into the metal atom.
Gain of Electrons
What is Oxidation?
The negative metal ions gain electrons at the positive electrode.
Loss of Electrons
What kind of reaction is this:
2Cl- → Cl2 + 2e-
Oxidation
What kind of reaction is this:
Cu2+ + 2e- → Cu
Reduction
What is a redox reaction?
Oxidation and Reduction are two halves of the same chemical reaction known as a REDOX reaction.
This is known as an ion-electron equation.
What is a DC and why must it be used?
A DC is a direct current supply of electricity and it must be used so that the products can be identified.
What happens when metals are heated with carbon?
They are reduced.
What are carbon and carbon monoxide referred to as?
Reducing agents.
Scientists need to be able to calculate the exact proportion of any ore which is actually the desirable metal.
How do they do this?
See snip - Percentage composition of ores
Scientists need to be able to calculate the exact proportion of any ore which is actually the desirable metal.
How do they do this?
See snip - Percentage composition of ores
When a metal element is reacting to form a compound then it is being ………. ?
Oxidised
What is an electrolyte?
An electrically conducting solution.
How are elements arranged in an electrochemical series?
Different pairs of metals produce different voltages. These voltages can be used to arrange the elements.
How does the electrochemical series determine the energy a metal releases when placed in an electrochemical cell?
The further apart the elements are in the electrochemical series, the greater the voltage produced when they are used to make an electrochemical cell.
Why can metals conduct electricity?
Due to their delocalised electrons which are free to move.
What is a displacement reaction?
When a metal pushes another out of a solution and takes its place in the solution.
Looking at the electrochemical series, how can you tell which metal could displace which?
A metal will displace another metal which is LOWER DOWN the electrochemical series, from its solution.
Name a metal which Magnesium could displace.
Zinc.
Give an example of a displacement reaction.
Magnesium placed in copper sulfate solution, copper metal was pushed out by the magnesium, and magnesium and magnesium sulfate solution was formed.
What do all metals above Hydrogen in the electrochemical series react with?
All metals above Hydrogen on the electrochemical series react with acid - as they can all displace Hydrogen ions as Hydrogen gas.
Give an example of a displacement reaction which involves a metal reacting with an acid.
Magnesium + sulfuric acid => Magnesium sulfate = Hydrogen (g)
What reactions do substances undergo in a displacement reaction? What does this mean?
The metal that is added to a solution (containing metal ions) undergoes oxidation.
The metal ions in the solution (or hydrogen ions in and acid) undergoes reduction.
This means that displacement reactions are redox reactions, as electrons are transferred from one reactant to another.
How do you write a REDOX reaction equation?
By combining the half equations (oxidation and reduction) and cancelling out the electrons on either side.
*Note: you must have the same number of electrons on either side of the equation to cancel them out. Sometimes you need to multiply them to make them equal.
What can be used to link two halves of electrochemical cells together?
A salt bridge (or ion bridge). This allows the ions to move across the bridge to complete the circuit.
In what direction do electrons flow in an electrochemical cell?
Through the wire in an electrochemical cell, electrons always flow from the more reactive to the less reactive metal.
Give two examples of energy sources which power objects through redox reactions.
Fuel cells and rechargeable batteries.
Identify two terms used to describe metals which can change shape whilst still retaining their strength?
- Malleable.
2. Ductile.
What does Malleable mean?
A metal which can be bent or hammered into shapes.
What does Ductile mean?
They can be pulled and squeezed to produce wires.
How does reshaping affect a metal chemically?
The metal ions and the ‘sea of electrons’ move position the metallic bonding remains unaffected.
How do we know that metals are strong?
Their melting and boiling points are high so it requires a lot of energy to break them.
Also, there is usually a large difference between the melting and boiling points of metals - called their liquid range.
What does the electrostatic attraction lie in metallic bonds?
Between the positive ions and the delocalised electrons.
