1.3 Properties of Transition Metals

Nickel has been used in making the electrodes in spark plugs in car engines for many years. Spark plugs are responsible for igniting the fuel in the combustion engine.

The material the electrodes are made of need to be able to withstand the very high temperatures and corrosive atmosphere found in the car engine and also be able to conduct electricity.

More recently, platinum has been used to make the electrode in spark plugs.

Table 1 shows some information about nickel and platinum.

Table 1

Evaluate the use of nickel and platinum for making the electrodes in spark plugs.

You should refer to the information in Table 1 and your knowledge about the properties of these metals in your answer.

Spark plugs with iridium electrodes are also available. They can last 25% longer than platinum spark plugs.

Iridium is six times harder than platinum with a melting point 700 ^oC higher. 

Suggest one other property of iridium.

Platinum, palladium and rhodium are all used within a catalytic convertor to remove harmful gases from the car's exhaust.

The catalytic convertor consists of a honeycomb structure which is coated with the metals. The exhaust gases travel through the catalytic convertor before leaving the vehicle.

Suggest why the convertor has a honeycomb structure.

Explain your answer.

Table 2 shows the amount of metals used in a catalytic convertor and the cost of each metal.

What is the total cost of the three metals used in the catalytic convertor?

Give your answer to the nearest pound.

The transition elements are metals which are found in the central section of the periodic table.

Group 1 elements are also metals.

Table 1 shows the melting point and oxide formulae of two elements from Group 1 and two transition elements

Use the data from Table 1 and your knowledge of Group 1 metals and transition metals to compare their chemical and physical properties.

Iron is another transition metal. When it reacts with oxygen, it can form different compounds which contain the Fe²⁺ ion or the Fe³⁺ ion.

Complete the two balanced symbol equations for the reaction between iron and oxygen to show how the different compounds are formed.

Formation of compound containing Fe²⁺ ions:   

___ Fe   +   ___ O₂   →   ______________

Formation of compound containing Fe³⁺ ions:   

___ Fe   +   ___ O₂   →   ______________

Sodium hydroxide was added to one solution containing Fe²⁺ ions and another solution containing Fe³⁺.

What observations would be made?

Observations with sodium hydroxide and solution containing Fe²⁺ ions:

________________________________________


Observations with sodium hydroxide and solution containing Fe³⁺ ions:

________________________________________

Iron can be used to displace copper from a solution of copper(II) sulfate.

Iron(II) sulfate is also formed. The equation for this reaction is:

Fe + CuSO₄ → FeSO₄ + Cu

Identify which species has been oxidised and which has been reduced.

You should include the ionic equation for the reaction and the two half equations in your answer.

Manganese can form compounds which are black, brown, pink, red, green, blue, and purple.

Why does manganese form different coloured compounds?

A compound of manganese, manganese dioxide, has the formula, MnO₂.

What is the charge on the manganese ion is manganese dioxide?

Manganese dioxide acts as a catalyst in the decomposition of hydrogen peroxide.

A student made the following statements about the role of manganese dioxide in this reaction:

"Manganese dioxide increases the rate of reaction by providing an alternative reaction pathway which has a lower activation energy.

The yield of oxygen produced increases as more oxygen can be produced in a given amount of time".

Is the student correct?

Explain your answer.

The diagram shows the reaction profile for the decomposition of hydrogen peroxide with a catalyst.

Figure 1

On Figure 1:

• Draw the reaction profile for the reaction without a catalyst
• Draw and label an arrow to show the activation energy for the reaction with a catalyst

What is the name used to describe the block of elements in the middle of the Periodic Table?

Some of the properties of the element called vanadium are shown below: 

• It has a high melting point and is solid at room temperature.
• It is a conductor of electricity and electricity.
• It forms coloured compounds.
• It forms crystalline compounds.
• It forms compounds that are used as catalysts.

From the list choose two properties which are considered typical of transition metals metals.

The transition elements have certain properties which make them very useful. 

Why is copper used to produce electrical wiring?

State why their compounds are used in glazing pottery. 

Why is iron used in the construction industry as girders in buildings?

An atom of titanium has the symbol,

Write down the number of protons, neutrons and electrons in this atom.

Protons       _____________________

Neutrons     _____________________

Electrons    _____________________

Using the Periodic Table, state why titanium is referred to as a transition element. 

Explain why titanium is a good conductor of electricity.

Rhodium is a typical transition metal.

Place a tick (✔) next to each of the four properties in the table that you would expect for rhodium.

Rhodium is used in the production of alloys and in ornaments and jewellery although its main use is in the automotive industry. 

It is used in the exhaust systems where it changes harmful unburned hydrocarbons, carbon monoxide, and nitrogen oxide emissions into less toxic gases.

Suggest two properties of rhodium that allows it to be used in this way.

Platinum and gold are used extensively in the production of wedding rings. 

They both have specific properties which makes them ideal for this use.

Tick (✔) two of these properties.

Iron oxide and cobalt oxide are used in glazing pottery. 

Iron (III) oxide contains the ions, Fe³⁺ and O^2-.

What is the formula of iron (III) oxide? 

Cobalt oxide can be reduced by hydrogen to form cobalt. 

Balance the equation below for this reaction:

CoO_{4   +   ___}H₂   →   Co   +   ___H₂O

Alloys can be made from cobalt mixed with other transition elements. 

These alloys are used to make cutting tools and knife edges which remain sharp at very high temperatures. 

They are often used to cut through other metals. 

Suggest two properties of transition metals that make them suitable for this purpose.

Potassium is a Group 1 element and chromium is a transition element. 

Identify three differences in their physical properties.