AQA GCSE FOUNDATION Chemistry: Metallic Bonding and Properties

AQA GCSE Foundation Chemistry: Metallic Bonding and Properties

Introduction

Metals are a fascinating class of materials that play a vital role in our daily lives. From the coins in your pocket to the buildings around you, metals are everywhere. Their unique properties, such as strength, conductivity, and malleability, are all a result of the special way their atoms bond together, known as metallic bonding.

Metallic Bonding

• Sea of Electrons: In metallic bonding, the metal atoms are closely packed together in a regular lattice structure. The outermost electrons of each atom are weakly held and become delocalised, forming a 'sea of electrons' that moves freely throughout the structure.
• Strong Electrostatic Attraction: The delocalised electrons are attracted to the positively charged metal ions, creating strong electrostatic forces that hold the lattice together.

Properties of Metals

1. Conductivity:

• Electrical Conductivity: The delocalised electrons can move freely throughout the metal lattice, allowing electricity to flow easily through the material.
• Thermal Conductivity: The delocalised electrons can also transfer heat energy quickly and efficiently, making metals excellent conductors of heat.

2. Malleability:

• Shape Changing: Metals are malleable because the layers of atoms can slide over each other without breaking the metallic bonds. This allows metals to be hammered or bent into different shapes.

3. Ductility:

• Wire Formation: Metals are ductile because they can be drawn into thin wires without breaking. This is also due to the ability of the atoms to slide over each other.

4. Strength and Hardness:

• Strong Metallic Bonds: The strong electrostatic forces in metallic bonding give metals their high tensile strength and hardness.

5. Lustre:

• Reflective Surface: Metals have a shiny appearance because the delocalised electrons can absorb and then re-emit light.

Summary

Metallic bonding is the key to understanding the properties of metals. The delocalised electrons are responsible for the excellent conductivity, malleability, and other unique characteristics that make metals valuable materials for a wide range of applications.