What is Metallic Bonding?
Metallic bonding is a type of chemical bonding that occurs in metals. It involves the attraction between positively charged metal ions and a sea of delocalised electrons. This structure gives metals their unique properties, such as high conductivity, malleability, and ductility. Read more about this on BBC bitesize here.
All metals conduct electricity because of their unique metallic bonding structure, find out more info here. In this type of bonding, the outer electrons are delocalised, meaning they are free to move. This creates a strong electrostatic attraction between the positively charged metal ions and the negatively charged delocalised electrons, allowing electrical conductivity.
Understanding metallic bonding is essential for SQA National 5 Chemistry, as it explains why metals behave the way they do in different chemical and physical contexts.
How Does Metallic Bonding Work?
In a metal, atoms are arranged in a regular lattice structure. Instead of being bound to one specific atom, the outer electrons of metal atoms are free to move throughout the structure. This is known as a “sea of delocalised electrons”, which creates strong electrostatic forces between the electrons and metal ions.
🔹 Key Features of Metallic Bonding:
- A lattice of positive metal ions
- A sea of delocalised electrons
- Strong electrostatic attractions between ions and electrons
Properties of Metals Explained by Metallic Bonding
Metallic bonding gives metals several important properties:
- High Electrical & Thermal Conductivity
- The delocalised electrons can carry charge and heat easily.
- Malleability & Ductility
- Metal atoms can slide over each other without breaking bonds, allowing metals to be shaped and stretched.
- High Melting & Boiling Points
- The strong electrostatic forces between ions and electrons require a lot of energy to break.
These properties explain why metals are used in electrical wiring, car bodies, and structural materials.
Examples of Metallic Bond
Common examples of metallic bonding include:
- Copper (Cu) → Used in electrical wiring due to high conductivity.
- Iron (Fe) → Strong and malleable, used in construction.
- Aluminium (Al) → Lightweight yet strong, used in aircraft and packaging.
Why is Metallic Bonding Important for SQA National 5 Chemistry?
Metallic bonding is a core topic in National 5 Chemistry, often appearing in:
✔️ Multiple-choice questions on properties of metals
✔️ Short-answer questions requiring explanations of conductivity and malleability
✔️ Extended response questions comparing different types of bonding
💡 Top Tip: Check past paper questions on metallic bonding to understand how the SQA might test this topic!
Why is Copper Highly Conductive?
Copper (Cu) is one of the best conductors of electricity due to its unique atomic structure and metallic bonding properties. It is widely used in electrical wiring, electronics, and power transmission.
1. Free Electrons & Metallic Bonding
Copper has one free electron per atom in its outermost shell (4s¹). These delocalised electrons move freely within the metal lattice, allowing electricity to flow with minimal resistance. The strong metallic bonding between copper atoms ensures these electrons remain mobile.
2. Low Electrical Resistance
Copper has low resistivity (1.68 × 10⁻⁸ Ω·m at 20°C), meaning electrons can move easily without losing much energy as heat. This makes copper ideal for:
✔ Electrical wires
✔ Power cables
✔ Printed circuit boards (PCBs)
3. High Thermal Conductivity
Copper is also an excellent thermal conductor (401 W/m·K), allowing efficient heat dissipation. This is why it’s used in:
✔ Heat sinks
✔ Cooking utensils
✔ Air conditioning systems
4. Ductility & Malleability
Copper is both ductile (can be drawn into thin wires) and malleable (can be shaped without breaking). This makes it practical for electrical applications where flexibility is needed.
5. Corrosion Resistance
Unlike iron, copper doesn’t rust. It forms a protective oxide layer (patina), preventing further corrosion. This ensures durability in electrical wiring and plumbing.
Summary: Why is Copper So Conductive?
- Delocalised electrons enable free movement of charge
- Low resistivity reduces energy loss
- Strong metallic bonding maintains conductivity
- Ductility & malleability make it easy to shape into wires
- Corrosion resistance ensures long-term reliability
Would you like a comparison between copper and other conductors like silver or aluminium? 🚀
FAQs on Metallic Bonding
❓ Why do metals conduct electricity?
Metals conduct electricity because their delocalised electrons are free to move and carry an electric charge.
❓ Why are metals malleable?
Metals are malleable because the layers of metal atoms can slide over each other without breaking the metallic bonds.
❓ What is the difference between metallic bonding and ionic bonding?
- Metallic bonding → Involves delocalised electrons shared among metal ions.
- Ionic bonding → Involves electron transfer between metals and non-metals, forming charged ions.
Below is a video about metallic bonding
Conclusion – National 5 Chemistry
Metallic bonding is crucial to understanding the properties of metals. For SQA National 5 Chemistry, knowing how metallic bonding works will help with exam questions on electrical conductivity, melting points, and metal properties.
🔹 Next Steps
- 📖 Revise past paper questions on metallic bonding.
- 🎯 Test yourself with online quizzes.
- 🧪 Explore real-world examples of metals in use!
