How It Works: Why Delocalised Electrons Create Unique Properties
Part of Metallic Bonding — GCSE Chemistry
This how it works covers How It Works: Why Delocalised Electrons Create Unique Properties within Metallic Bonding for GCSE Chemistry. Revise Metallic Bonding in Bonding & Structure for GCSE Chemistry with 20 exam-style questions and 20 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 4 of 11 in this topic. Use this how it works to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 4 of 11
Practice
20 questions
Recall
20 flashcards
⚙️ How It Works: Why Delocalised Electrons Create Unique Properties
The "sea of delocalised electrons" model explains all of the distinctive properties of metals through one fundamental principle: mobile electrons.
Electrical conductivity: When a voltage is applied across a metal, the delocalised electrons experience a force in one direction — they drift towards the positive terminal, creating a flow of charge. This is electric current. Unlike ionic compounds (which require melting or dissolving to allow ion movement), metals can conduct in the solid state because their electrons are already free.
Thermal conductivity: When part of a metal is heated, the electrons in that region gain kinetic energy and move faster. Because they are free to move throughout the metal, they rapidly transfer this kinetic energy to other electrons and ions throughout the structure. This is why metal saucepans heat up quickly and evenly.
Malleability and ductility: When force is applied, layers of positive metal ions can slide over each other. In an ionic crystal, this would bring like charges into alignment (causing repulsion and fracture). In a metal, the delocalised electron sea moves with the ions — maintaining the attractive force throughout the deformation. The bond is non-directional and non-specific, so it can accommodate ion movement. This is why metals bend rather than shatter.
Quick Check: Why can metals conduct electricity in the solid state, but ionic compounds cannot?
In metals, delocalised electrons are free to move throughout the solid structure, carrying electrical charge even when solid. In ionic compounds, the ions are fixed in the lattice and cannot move — so no conduction is possible until the compound is melted or dissolved, when the ions become free to move.