AQA · GCSE · Chemistry
Course version: 8462 · Version from Sept 2018
The electrons in the outer shell of metal atoms are delocalised and so are…
Full specification wording
Metallic bonding: The electrons in the outer shell of metal atoms are delocalised and so are free to move through the whole structure. The sharing of delocalised electrons gives rise to strong metallic bonds. The bonding in metals may be represented in the following form: AQA GCSE Chemistry 8462. GCSE exams Jun
In a metal, the outer-shell electrons are not held by any one atom.
Checked against the AQA 8462 specification (opens in a new tab) on .
- Point 2 of 2
- 2 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
In a metal, the outer-shell electrons are not held by any one atom. They become delocalised, meaning they are shared across the whole giant lattice and are free to move. The positive metal ions that remain are arranged in a regular pattern, and the sea of delocalised electrons is attracted to these ions in all directions. This electrostatic attraction between the positive ions and the shared electrons is the metallic bond, and because it acts throughout the structure it is strong. The model is often drawn as positive ions in a regular lattice with negative delocalised electrons between them. Moving electrons explain why metals conduct electricity and heat, while the strong bonding explains high melting points. When answering, refer to delocalised electrons, free movement, positive ions and strong electrostatic attraction.
What earns the marks
- States that outer-shell electrons in a metal become delocalised.
- Explains that delocalised electrons are free to move through the whole structure.
- Describes the metal as positive ions in a regular lattice surrounded by delocalised electrons.
- Identifies the metallic bond as the electrostatic attraction between positive ions and delocalised electrons.
- Links delocalised electrons to electrical or thermal conductivity.
- Links strong metallic bonding to high melting and boiling points.
Common mistakes and how to put them right
Saying that metal atoms share pairs of electrons in the same way as covalent bonds.
Put it right by describing delocalised electrons shared across the whole lattice.
Describing the metal as negative ions.
Put it right by stating that the lattice contains positive metal ions.
Claiming that the delocalised electrons are fixed in place.
Put it right by stating that they are free to move throughout the structure.
Exam tips
- Use the phrase sea of delocalised electrons when describing the model.
- Always name the two charged species involved in the metallic bond before explaining the attraction.
- When explaining conductivity, state that the delocalised electrons carry charge or energy through the metal.
Try the lesson
The start of the Metallic bonding: The electrons in the outer shell of metal atoms are delocalised and so are free to move through the whole structure. The sharing of delocalised electrons gives rise to strong metallic bonds. The bonding in metals may be represented in the following form: AQA GCSE Chemistry 8462. GCSE exams Jun lesson, made from checked teaching notes for this specification point.
Have a go first
In a metal, what happens to the electrons in the outer shell of each metal atom?
Listen
In a metal, the outer-shell electrons are not held by any one atom. They become delocalised, meaning they are shared across the whole giant lattice and are free to move. The positive metal ions that remain are arranged in a regular pattern, and the sea of delocalised electrons is attracted to these ions in all directions. This electrostatic attraction between the positive ions and the shared electrons is the metallic bond, and because it acts throughout the structure it is strong. The model is often drawn as positive ions in a regular lattice with negative delocalised electrons between them. Moving electrons explain why metals conduct electricity and heat, while the strong bonding explains high melting points. When answering, refer to delocalised electrons, free movement, positive ions and strong electrostatic attraction. A strong answer earns marks for these points. States that outer-shell electrons in a metal become delocalised. Explains that delocalised electrons are free to move through the whole structure. Describes the metal as positive ions in a regular lattice surrounded by delocalised electrons. Identifies the metallic bond as the electrostatic attraction between positive ions and delocalised electrons. A common slip: Saying that metal atoms share pairs of electrons in the same way as covalent bonds. Instead, describing delocalised electrons shared across the whole lattice. Exam tip: Use the phrase sea of delocalised electrons when describing the model.
Key words
Say what each word means before you turn the card.
Metallic bonding
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Delocalised electrons
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See every definition
- Metallic bonding
- The electrostatic attraction between the positive ions and the shared delocalised electrons, acting throughout the structure so it is strong.
- Delocalised electrons
- Outer-shell electrons that are not held by any one atom and are free to move through the whole structure.
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Test your understanding of Metallic bonding: The electrons in the outer shell of metal atoms are delocalised and so are free to move through the whole structure. The sharing of delocalised electrons gives rise to strong metallic bonds. The bonding in metals may be represented in the following form: AQA GCSE Chemistry 8462. GCSE exams Jun
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