GCSE · Chemistry · AQA · Spec 8462

Metallic bonding

Ionic bonding hands an electron to a partner. Covalent bonding locks a pair between two atoms. A metal lets its outer electrons go — to every atom at once.

Chemistry · Bonding

Where do a metal's outer electrons go?

There are three types of strong chemical bond. Step through all three and watch the outer electrons each time — tab 03 is the one this lesson is about.

Metal (Na)Non-metal (Cl)Active electron

Ionic bonding

Sodium chloride (NaCl)

Bond formed by

Transfer: an outer electron moves from the metal atom to one non-metal atom

Here an electron is handed from one atom to one particular partner — sodium to chlorine. The electron ends up with a new owner. Keep that picture for tab 03.

The metallic bond

Reason it through

If the electrons in a metal are free to move, why are metallic bonds strong?

Link 1 of 4

First link · your turn

Start with one metal atom in the giant structure. What happens to its outer-shell electrons?

Locked — reveal the link above first

Check your picture

What does 'sharing' mean in a metal?

Metallic bonding is described as metal atoms sharing delocalised electrons. Covalent bonding is described as atoms sharing electrons too.

Which is closest to what you picture when a metal's atoms 'share' electrons?

Each metal atom shares a pair of electrons with the atom next to it, like in covalent bonding.The electrons wander about freely, so they can't really be holding anything together — metallic bonds must be weak.One metal atom gives its outer electrons to another metal atom, like in ionic bonding.The outer-shell electrons leave their own atoms and are shared by the whole structure — no single atom owns them.

How sure are you?

I'm sureI think soI'm guessing

Each metal atom shares a pair of electrons with the atom next to it, like in covalent bonding.

This is a common misconception

That is the covalent picture, and it is the most common mix-up here. In a metal there are no fixed pairs sitting between two neighbours. The delocalised electrons are not tied to any one place: each one is free to move through the whole structure, so every ion shares in all of them at once.

The electrons wander about freely, so they can't really be holding anything together — metallic bonds must be weak.

This is a common misconception

Moving electrons are still negative. Wherever they go, they are attracted to the positive metal ions around them — that is the chain you just followed. Because the sea of electrons is shared by every ion, the attraction acts throughout the structure, and metallic bonds are strong.

One metal atom gives its outer electrons to another metal atom, like in ionic bonding.

This is a common misconception

In ionic bonding an electron goes to one particular partner, which becomes a negative ion. In a metal no atom receives the electrons and there are no negative metal ions: every metal atom becomes a positive ion, and the electrons it released belong to the structure as a whole.

The outer-shell electrons leave their own atoms and are shared by the whole structure — no single atom owns them.

This matches the evidence

Yes. That is what 'delocalised' means: the outer-shell electrons belong to the whole giant structure, not to any one atom or pair of atoms, and they are free to move through all of it.

In a metal, 'shared' means shared by everyone: the delocalised electrons belong to the whole structure, not to one atom and not to one pair.

Chemistry · Bonding

Which strong bond holds it together?

Which type of strong bonding holds each substance together?

Still to sort

Ionic (0)

A metal combined with a non-metal: electrons are transferred.

Covalent (0)

Non-metal atoms only: electrons are shared in pairs.

Metallic (0)

Metal atoms only — a metallic element or an alloy: outer-shell electrons are delocalised.

Where the line is: An alloy is still metallically bonded. Mixing two metals does not turn the bonding ionic or covalent — the atoms are all metal atoms sharing delocalised electrons.

5 of 5 still to sort.

Place each substance under the type of strong bond that holds it together. Look at what kinds of atoms it is made from.

Put it in your own words

Describe and explain the bonding in a metal

Describe the structure of a metal and explain how metallic bonding holds it together. [4 marks]

Your answer

0 words · your answer stays on this page and is not sent anywhere.

The mark scheme

A giant structure of atoms (or positive ions) arranged in a regular pattern. (1 mark)
The outer-shell electrons of the metal atoms are delocalised. (1 mark)
The delocalised electrons are free to move through the whole structure / are shared by all the ions. (1 mark)
Strong electrostatic attraction between the positive metal ions and the delocalised electrons (this is the strong metallic bond). (1 mark)

Model answer

A metal is a giant structure in which the atoms are arranged in a regular pattern. The outer-shell electrons of the metal atoms are delocalised, so they are free to move through the whole structure and are shared by all the atoms, which are left as positive ions. There is a strong electrostatic attraction between the positive metal ions and the delocalised electrons, and this attraction is the strong metallic bond.

Name the structure, say what the outer-shell electrons do, then name the attraction and say it is strong — four separate points.

WHAT YOU'VE LEARNED

A quick recap of today's lesson.

In a metal, the outer-shell electrons leave their own atoms and are shared by the whole structure — and that shared sea is what holds the metal together.

What you need to know

There are three types of strong chemical bond: ionic, covalent and metallic.
Metals consist of giant structures of atoms arranged in a regular pattern.
The outer-shell electrons of metal atoms are delocalised: they are free to move through the whole structure.
Once its outer-shell electrons are delocalised, each metal atom is left as a positive metal ion.
The sharing of delocalised electrons gives strong metallic bonds: there is strong electrostatic attraction between the positive metal ions and the delocalised electrons.
Metallic bonding occurs in metallic elements and in alloys.

The big picture

There are three types of strong chemical bond: ionic, covalent and metallic. Metals consist of giant structures of atoms arranged in a regular pattern. The electrons in the outer shell of the metal atoms are delocalised, so they are free to move through the whole structure, leaving positive metal ions. The strong electrostatic attraction between these ions and the shared delocalised electrons is the metallic bond, and it is strong. Metallic bonding occurs in metallic elements and in alloys.

Key points

1Ionic: an electron goes to one partner. Covalent: a pair is shared by two atoms. Metallic: outer electrons are shared by the whole structure.

2Metal = giant structure, regular pattern, positive ions in a sea of delocalised electrons.

3Delocalised electrons move freely but stay attracted to the positive ions — the bond is strong.

4Pure metals and alloys are both held together by metallic bonding.

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Worked example

Problem

A textbook diagram of a metal shows rows of identical circles, each marked '+', with small dots marked 'e⁻' spread between them. A student says: 'The dots are in the wrong place — the electrons should be drawn in the shells of the atoms.' Explain what each part of the diagram shows, and why the student is wrong.

⚠ Watch out

Writing only that metal atoms 'share electrons', or drawing a shared pair between two metal atoms. That describes covalent bonding. Say that the outer-shell electrons are delocalised and shared by the whole structure, then name the strong electrostatic attraction between the positive metal ions and those electrons.

🧠

Memory hook

Ionic gives, covalent pairs, metallic pools: in a metal, the outer electrons belong to everyone.

✓

Check yourself

In one sentence each: where do the outer electrons go in ionic, covalent and metallic bonding — and which is the only one where no single atom owns them?

Flashcards

(10)

What are the three types of strong chemical bond?

Ionic, covalent and metallic.

Which substances are held together by metallic bonding?

Metallic elements and alloys.

How are the atoms arranged in a metal?

In a giant structure, arranged in a regular pattern.

Which electrons become delocalised in a metal?

The electrons in the outer shell of each metal atom.

What does 'delocalised' mean for an electron in a metal?

It does not belong to any one atom and is free to move through the whole structure.

A metal atom's outer-shell electrons are delocalised. What is left behind?

A positive metal ion (it keeps all its protons but has lost negative electrons).

What is the metallic bond?

The strong electrostatic attraction between positive metal ions and the delocalised electrons they share.

Metallic vs covalent: how is the 'sharing' different?

Covalent: a pair of electrons shared between two atoms. Metallic: delocalised electrons shared by the whole structure.

Metallic vs ionic: what happens to the outer electrons?

Ionic: transferred to one non-metal partner, making a negative ion. Metallic: no partner receives them — they join the shared sea and every metal particle becomes a positive ion.

Brass is a mixture of copper and zinc. What bonding holds it together?

Metallic bonding — brass is an alloy, and alloys are metallically bonded like pure metals.

Tap any card to flip it, or use Study as deck to go through them one at a time. In the full lesson these run as a spaced-repetition deck — you rate each card Hard, Good or Easy and the tricky ones keep coming back until they stick.

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Where do a metal's outer electrons go?

What does 'sharing' mean in a metal?

Which strong bond holds it together?

Describe and explain the bonding in a metal

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