5.6Metallic Bond
Electrical wires made of metal are widely used to conduct electricity, but exposed wires can pose an electric shock hazard. This note covers how metallic bonds are formed in metals and explains the mechanism behind the electrical conductivity of metals.
Learning Objectives
- Explain the formation of a metallic bond.
- Reason out the electrical conductivity of metal.
Formation and Electrical Conductivity of Metallic Bond
A lattice of positively-charged metal ions immersed in a sea of delocalised electrons.
Brief Explanation
Understand how metallic bonds form and why metals conduct electricity.
1. Arrangement of Metal Atoms
Metal atoms are arranged closely packed and orderly in the solid state. Valence electrons of metal atoms can be donated easily and delocalised, even in the solid state.
2. Formation of Metallic Bond
When the valence shells of metal atoms overlap, a sea of electrons is formed. The electrostatic attraction force between this sea of electrons and the positively-charged metal ions forms the metallic bond.
| Concept | Explanation |
|---|---|
| Delocalised electron | An electron that moves freely and is not owned by any atom nor ion. |
| Sea of electrons | Formed when the valence shells of metal atoms overlap, resulting in electron delocalisation. |
| Positively-charged metal ion | A cation formed when a metal atom's valence electrons become delocalised. |
| Electrical conductivity | The ability of a metal to conduct electric current through the movement of freely moving electrons carrying charges between terminals. |
Try These Questions First
Answer mentally, then check the explanation.
What is meant by a delocalised electron?
How is a metallic bond formed?
Why can metals conduct electricity in the solid state?
Common Mistakes
Avoid these errors when explaining metallic bonding.
Common Misconceptions
Compare each misconception with the correct fact.
Metals only form ions in molten or aqueous states.
In metallic bonding, positively-charged metal ions are already formed in the solid state when valence electrons become delocalised.
Electrons flow from the positive terminal to the negative terminal.
Free electrons carry electrical charges from the negative terminal to the positive terminal when electricity is supplied.
Summary
Key facts to remember.
- Metals consist of closely packed, orderly arranged atoms whose valence shells overlap, creating a sea of freely moving delocalised electrons.
- The electrostatic attraction between this sea of electrons and the resulting positively-charged metal ions constitutes the metallic bond.
- When electricity is supplied, these delocalised electrons move from the negative terminal to the positive terminal, enabling the metal to conduct electricity.
Quick Activity
Complete all parts before checking your score.
A. Objective Quiz
What holds the particles together in a metallic bond?
How do metals conduct electricity when connected to an electrical circuit?
B. Fill in the Blanks
A sea of electrons is formed when the valence shells of metal atoms ______, resulting in electron delocalisation.
Positively-charged metal ions are formed when valence electrons are ______.
C. Match the Concept with Its Description
Drag each concept on desktop. On mobile, tap a concept and then tap the matching box.
Answer Choices
Delocalised electron Sea of electrons Metallic bond Electrical conductivityDescription Matching
Keywords
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