Metals

Physical Properties of Metals

• Pure metals allow their ions to slide over each other, a characteristic shown in the provided table and figure.
• Alloys like brass and steel are created by mixing metallic elements with others to enhance strength and prevent deformation.
• The differing sizes of ions in alloys inhibit sliding, improving shape retention compared to pure metals.

Reactivity Series

• Highly reactive metals like potassium and sodium react vigorously with cold water, while others react more slowly.
• Metals above hydrogen in the series can react with dilute acids to produce salts and hydrogen.
• The reactivity of metals influences their ability to displace other metals from compounds.

Ionic Equations and Displacement Reactions

• Magnesium can displace copper due to its higher reactivity, forming positive ions more readily.
• Zinc powder heated with copper(II) oxide demonstrates a similar displacement reaction.
• No reaction occurs when zinc oxide is heated with copper, highlighting the importance of reactivity.

Deducing Order of Reactivity

• Electrochemical cells can determine reactivity order by measuring the EMF between dissimilar metals.
• The more reactive metal acts as the negative terminal in these cells.
• Voltmeter readings provide quantitative measures of reactivity differences.

Unexpected Behavior of Aluminium

• Aluminium's protective oxide layer inhibits its reactivity until removed.
• Anodising intentionally creates this protective layer for various applications.
• This property allows aluminium use in applications typically reserved for less reactive metals.

Thermal Decomposition of Metallic Compounds

• Metals at the top of the reactivity series are more stable to heat.
• The stability of metal compounds varies, affecting their decomposition products.
• Understanding thermal decomposition is crucial for predicting metal compound behavior.

Extraction of Metals

• Ease of extraction generally increases down the reactivity series.
• Very reactive metals require electrolysis for extraction.
• Aluminium extraction is costly due to high electricity requirements and temperature needs.

Iron Extraction

• The blast furnace process uses hematite, coke, and limestone.
• Coke reacts exothermically with oxygen, producing carbon monoxide for iron reduction.
• Limestone removes impurities, forming slag usable in construction.

Recycling Metals

• Recycling conserves resources and reduces landfill waste.
• It's cost-effective due to lower energy requirements compared to ore extraction.
• Challenges include collection costs and potential purity issues in recycled metals.

Conversion of Iron into Steel

• The properties of steel are influenced by transition elements added during conversion.
• The basic oxygen process removes impurities by blowing oxygen onto molten iron.
• Carbon content is controlled to produce various types of steel, including mild and stainless steel.

Zinc Extraction

• Zinc extraction involves heating zinc oxide with powdered coke.
• This process produces zinc vapor that condenses into molten zinc.
• The method highlights the importance of thermal processes in metal extraction.

Copper Refining

• Copper is refined through electrolysis, with impure copper as the anode and pure copper as the cathode.
• Impurities either dissolve or settle at the bottom during the process.
• This process ensures high electrical conductivity in copper products.

Recycling Aluminium and Iron/Steel

• Recycling metals conserves natural resources and reduces landfill waste.
• The process is cost-effective due to lower energy requirements compared to ore extraction.
• Challenges include collection costs and potential purity issues in recycled metals.

Key Conclusions

• The reactivity series significantly influences metal extraction methods.
• Coke plays a dual role in iron extraction as fuel and reducing agent.
• Aluminium extraction is expensive due to high electricity costs, highlighting the need for efficient energy use.
• Recycling metals extends the lifespan of natural resources but faces challenges in collection and purity maintenance.
• Understanding thermal decomposition of metal compounds is crucial for predicting their behavior under heat.

Metal Properties and Reactions Quiz

Test your knowledge on metal properties, reactivity, and industrial processes

Metal Properties and Reactions

Question 1 Easy

Explain why metals are ductile and malleable.

Analysis:

Metals are ductile and malleable because their metallic bonds allow the metal atoms to slide past each other without breaking the bonds.

Question 2 Medium

What is meant by the reactivity series of metals and how is this series determined?

Analysis:

The metal reactivity series shows the order of metal reactivity, with the most reactive metal at the top. This order is determined based on the reaction of the metal with water, acids, and salts of other metals.

Question 3 Medium

Write the equation for the reaction between magnesium and copper(II) sulfate solution.

Analysis:

Mg(s) + CuSO4(aq) → MgSO4(aq) + Cu(s)

Question 4 Medium

Why can aluminum, although relatively reactive, be used for materials such as beverage cans?

Analysis:

Aluminum forms a strong and tightly adherent oxide layer on its surface. This layer protects the aluminum from further corrosion.

Question 5 Hard

Name the products produced from the thermal decomposition of copper(II) nitrate.

Analysis:

Copper (II) oxide (CuO), nitrogen dioxide gas (NO2), and oxygen gas (O2).

Question 6 Medium

What is the function of coke in the extraction of iron from hematite?

Analysis:

Coke acts as a reducing agent by reacting with oxygen to form carbon dioxide, which then reacts with coke again to form carbon monoxide. This carbon monoxide is what reduces hematite to iron.

Question 7 Medium

Briefly explain the process of converting iron into steel.

Analysis:

Conversion of iron to steel involves the removal of most non-metallic impurities and the addition of transition elements in controlled amounts to obtain the desired properties.

Question 8 Hard

Why is aluminum extracted through electrolysis rather than chemical reduction?

Analysis:

Aluminum is so reactive that it cannot be reduced by common reducing agents. Electrolysis is used to extract aluminum from molten aluminum oxide.

Question 9 Medium

What are the main advantages of recycling metals such as aluminum and iron/steel?

Analysis:

Recycling metals prevents the depletion of natural resources and reduces waste and pollution resulting from the extraction of new metals.

Question 10 Easy

Name two uses of copper and relate them to its supporting properties.

Analysis:

1. Electrical cables: Copper's high electrical conductivity makes it ideal for this use.

2. Cookware: Copper's high thermal conductivity and high melting point make it suitable for cooking utensils.