Introduction
- Metals are some of the most important materials in the world.
- Their strength, durability, and ability to conduct heat and electricity make them very useful.
- However, metals also have weaknesses, such as rusting, and sometimes need to be improved by mixing them with other elements.
- In this blog, we’ll look at the properties of transition metals, the problem of corrosion, how rusting can be prevented, and why alloys are stronger and more useful in everyday life.
- Here are some common examples that show why alloys are stronger and more useful:
Steel (iron + carbon): Stronger than pure iron, used in buildings and bridges.
Bronze (copper + tin): Harder than copper, used for statues and medals.
Brass (copper + zinc): Strong and shiny, used in musical instruments.
Transition Metals in the Periodic Table
- Transition metals are elements found in the d-block of the Periodic Table, specifically between Group 3 and Group 12.
- They are called transition metals because they form a “transition” between the highly reactive metals on the left and the less reactive metals and non-metals on the right.
What Are The Properties of Transition Metals?
- In the middle of the periodic table, we find transition metals, which have special features that make them different from other elements:
Strength and Durability
- Transition metals are stronger than most other metals, so they are used in construction, machines, and tools.
- For example, iron and steel are used in bridges and tall buildings.
Good Conductors
- They allow heat and electricity to flow through them easily.
- For example, electrical copper is used in wires and cooking pans.
Malleable and Ductile
- This means they can be hammered into thin sheets or stretched into wires without breaking.
- Metals like gold and copper are especially good at this.
Coloured Compounds
- Transition metals form compounds that are brightly coloured.
- For example, copper sulfate is blue, potassium dichromate is orange, and nickel compounds are green.
Catalysts
- Some transition metals help reactions happen faster without getting used up.
- For example, iron is used in making ammonia, and platinum helps reduce car pollution.
What is Corrosion of Metals?
- When metals are slowly damaged by chemical reactions with substances in their surroundings, such as air, water, or acids, it is called corrosion.
- The most common example of corrosion is rusting of iron.
- When iron reacts with Oxygen and water, it forms reddish-brown flakes called rust.
- Rust is soft and crumbly, so instead of protecting iron, it makes the metal weaker.
- This changes into Fe₂O₃·xH₂O (hydrated iron(III) oxide), which we call rust.
Here are some different types of corrosion on metals:
Iron:
- Rust – the reddish-brown corrosion that weakens bridges, car etc.
Copper:
- Patina – a green layer that develops on old roofs and statues.
Silver:
- Tarnish – a black coating formed by silver sulfide.
Aluminium:
- Aluminium oxide – a thin, protective layer that stops further corrosion.
What Are The Methods of Preventing Rusting?
- There are different methods we can use to prevent rusting. Here they are:
Painting and Plastic Coating
- A layer of paint or plastic is used on car bodies, fences, etc., which keeps out air and water.
Oiling or Greasing
- It is commonly used for machine parts and bicycle chains.
- The oil prevents water and oxygen from reaching the metal.
Galvanising
- When iron is coated with a layer of zinc, it is called galvanising.
- The zinc protects the iron by forming a barrier, and even if it is scratched, zinc reacts more easily than iron, so it prevents rusting.
Electroplating
- Using electricity, a thin layer of another metal such as chromium or silver is coated onto iron or steel.
- This protects it from rust and also makes it look better.
Alloying
- When iron is mixed with other metals, such as chromium and nickel, it makes stainless steel.
- This process is called alloying, and the steel does not rust easily, so it is used in cutlery, sinks, and medical tools.
Need help with Transition Metals?
Our tutors explain it step by step, matched to your exam board.
Book a Consultation →What Makes Alloys Stronger?
- Pure metals are not always suitable for everyday use, so alloys are made to improve their strength and usefulness.
- Here are the main reasons why alloys are stronger than pure metals:
Pure Metals are too Soft
- On their own, many pure metals bend or wear out quickly, so they are not always useful for construction or tools.
Alloys are Mixtures
- When metals are mixed with other metals (or non-metals), the new material is usually stronger and more durable.
Layers in Pure Metals Slide Easily
- Because all atoms are the same size and neatly arranged, the layers can slip over each other, making the metal soft.
Different Atom Sizes in Alloys
- When other elements are added, they break the regular pattern of atoms, so the layers can’t slide easily.
- This makes the alloy harder and stronger.
Examples of alloys:
- Pure iron is soft and bends easily.
- Adding small amounts of carbon makes steel, which is much stronger.
- Adding chromium and nickel makes stainless steel, which is both strong and resistant to rust.
What Are The Types of Alloy Steels?
- Steel is an alloy of iron and carbon.
- By adding other elements, we can make different types of steel with special properties.
- Here are some examples:
Stainless Steel
- Made with chromium and nickel.
- It is commonly used in cutlery, kitchen sinks, medical instruments, etc., because it doesn’t rust easily.
High-Carbon Steel
- It contains more carbon, which makes it very hard and strong.
- It is used for knives, drills, and other cutting tools.
Low-Carbon Steel
- It contains less carbon, which makes it softer and easier to shape.
- It is used in car bodies and household appliances.
Tool Steel
- It contains elements like tungsten and vanadium, which make it tough and heat-resistant.
- It is used in machine parts and tools.
What Are The Uses of Metals and Alloys?
- Metals and alloys are everywhere in daily life:
Construction
- Steel is used for bridges, buildings, and railways because it is strong and durable.
Transport
- Aluminium is used for aircraft because it is lightweight, while steel is used for ships and cars for strength.
Electrical uses
- Copper is used in wires and electrical circuits because it conducts electricity very well.
Household items
- Stainless steel is used in cutlery, pans, sinks, and appliances.
Jewellery and Decoration
- Gold, silver, and platinum are used in jewellery.
- Cheaper items are often electroplated to look more expensive.
Coins
- Made of different alloys to be strong and long-lasting.
Frequently Asked Questions
Solution:
Transition metals are elements found in the centre of the periodic table that form coloured compounds and have variable oxidation states.
Solution:
They are found in the middle block (Groups 3–12) of the periodic table.
Solution:
They are hard, strong, shiny, good conductors of heat and electricity, and have high melting points.
Solution:
Because they are strong and durable, they are used in buildings, cars, and machinery.
Solution:
Corrosion is the gradual destruction of metals by reacting with air or water, such as the rusting of iron.
Solution:
Rusting is a type of corrosion where iron reacts with oxygen and water to form hydrated iron(III) oxide (rust).
Solution:
Rusting can be prevented by painting, oiling, galvanising, or coating the metal to stop oxygen and water from reaching it.
Solution:
In alloys, different-sized atoms make it harder for metal layers to slide over each other, increasing strength and hardness.
Solution:
Alloy steels are steels mixed with other elements like chromium or nickel to improve properties such as strength and resistance to rust.
Solution:
Metals and alloys are used in construction, transport, electrical wiring, coins, tools, and jewellery due to their strength and conductivity.
