GCSE · Chemistry · AQA · Spec 8462

Ionic bonding

Electrons jump between atoms — creating charged ions locked together by electrostatic force.

What you need to know

  • Ionic bonding occurs between metals and non-metals via electron transfer.
  • Metals lose electrons to form positive ions; non-metals gain electrons to form negative ions.
  • Ion charges follow group number: Group 1 → 1+, Group 2 → 2+, Group 6 → 2−, Group 7 → 1−.
  • An ionic bond is the strong electrostatic force of attraction between oppositely charged ions, acting in all directions.

The big picture

Ionic bonding forms when a metal atom transfers one or more electrons to a non-metal atom. The metal becomes a positively charged ion and the non-metal becomes a negatively charged ion. The strong electrostatic force of attraction between these oppositely charged ions — acting in all directions — is the ionic bond. The charges on the ions can be predicted directly from the element's group number.

TONIGHT'S REVISION

Ionic Bonding

How electron transfer between metals and non-metals creates charged ions held together by electrostatic attraction.

Chemistry · Bonding

Ionic Bonding Explorer

See what happens when a metal meets a non-metal — electrons transfer, ions form, and the bond locks in.

NaSodium · 2,8,1ClChlorine · 2,8,7→ Cltransfer 1 electronNa⁺Cl⁻
Metal (Na)Non-metal (Cl)Active electron

Ionic bonding bonding

Sodium chloride · NaCl

Bond formed by

Electron transfer

Structure

Giant ionic lattice

Melting point

High (801 °C)

Conducts?

Only when molten or dissolved

A sodium atom (Group 1) loses its 1 outer electron to a chlorine atom (Group 7), which needs just 1 more electron to fill its outer shell. Na becomes Na⁺; Cl becomes Cl⁻. The strong electrostatic force of attraction between the oppositely charged ions — acting in all directions — is the ionic bond.

Exam line: For AQA, always name the bond type AND explain it: 'electrostatic force of attraction between oppositely charged ions' earns the mark — 'attraction between ions' alone does not.
Watch out: Ionic bonding is metal + non-metal with electron TRANSFER. Covalent is non-metal + non-metal with electron SHARING. These are the two most confused bonding types.

Predict, then check

Think about what the group number tells you — then commit.

A magnesium atom (Group 2) reacts with an oxygen atom (Group 6). What ions are formed, and what is the formula of the compound?

Electron transfer in sodium chloride

Follow where the electron goes — from the metal to the non-metal.

Tap a molecule to see what it does in the reaction.

Ionic bonding — the causal chain

?

Reason it through

Why does an ionic bond form between a metal and a non-metal?

Link 1 of 3

First link · your turn

What does a metal atom need to do with its outer electrons to become stable?

2
Locked — reveal the link above first
3
Locked — reveal the link above first

Relationship matrix

Tap any cell to reveal it. Tap a column header to read one property down every item.

Loses or gains electrons?Ion charge formedNoble gas configuration achieved
Sodium (Na)Group 1
Magnesium (Mg)Group 2
Chlorine (Cl)Group 7
Oxygen (O)Group 6

Each cell hides a short answer and the reason behind it. Predict before you tap.

Cross-subject · Exam skill

AQA command words — ionic bonding

Know what the examiner is actually asking before you write a word.

ExplainBloom · Understand

01Definition

Give a reason WHY — state the cause and its effect. A description alone will not score.

02Mark-band signal

Each 'because' earns a mark — AQA ionic-bonding explain answers are typically 3 marks: (1) metal loses electrons → positive ion, (2) non-metal gains electrons → negative ion, (3) ionic bond is electrostatic attraction between oppositely charged ions.

03Sentence stems

  • Explain why sodium chloride is an ionic compound.
  • Explain the formation of the ionic bond in magnesium oxide.
  • Explain why the ions formed are stable.

04Common mistake

Writing 'they are attracted to each other' without using the word 'electrostatic' — AQA mark schemes often require this specific term.

Exam line: AQA 8462: 'Explain ionic bond formation' is the highest-frequency question type for this topic. Use 'electrostatic force of attraction' — not just 'attraction'.
Watch out: Command words are not interchangeable. 'Describe' and 'Explain' are worth different things — misreading the command word is a self-inflicted mark loss.

Key points

1Metal atoms LOSE electrons → positive ions (cations); non-metal atoms GAIN electrons → negative ions (anions).
2Both ions end up with the stable electronic structure of a noble gas.
3Ion charge = group number with sign: Group 2 metal loses 2e⁻ → 2+ ion.
4The ionic bond is the electrostatic attraction between oppositely charged ions — it acts in ALL directions.
5Dot-and-cross diagrams show electron transfer for Groups 1/2 metals with Groups 6/7 non-metals only.

Worked example

Problem

Use a dot-and-cross diagram to show the formation of magnesium oxide (MgO) and state the charge on each ion formed.

🧠

Memory hook

LEO the lion says GER — Lose Electrons Oxidised, Gain Electrons Reduced. Metals go LEO (lose, become +); non-metals go GER (gain, become −).

★ Exam tip

AQA often asks you to 'explain' ionic bond formation — always state THREE things: (1) the metal loses electrons to form a positive ion, (2) the non-metal gains electrons to form a negative ion, (3) the ionic bond is the electrostatic attraction between the oppositely charged ions. One mark per point.

⚠ Watch out

Writing that ions 'share' electrons — electrons are TRANSFERRED in ionic bonding, not shared (sharing is covalent).

✓

Check yourself

Without looking — what is the charge on a calcium ion, and why does it have that charge?

Flashcards

(24)
What type of elements form ionic bonds?
A metal combined with a non-metal.
What happens to the metal atom during ionic bonding?
It loses electrons and becomes a positively charged ion (cation).
What happens to the non-metal atom during ionic bonding?
It gains electrons and becomes a negatively charged ion (anion).
What electronic structure do the ions achieve after electron transfer?
The stable electronic structure of a noble gas (full outer shell).
Define an ionic bond.
The strong electrostatic force of attraction between oppositely charged ions, acting in all directions.
What is the charge on a Group 1 ion?
1+ (e.g. Na⁺, Li⁺, K⁺).
What is the charge on a Group 2 ion?
2+ (e.g. Mg²⁺, Ca²⁺).
What is the charge on a Group 7 ion?
1− (e.g. Cl⁻, F⁻, Br⁻).
What is the charge on a Group 6 ion?
2− (e.g. O²⁻, S²⁻).
What is the charge on a sodium ion and why?
Na⁺ — sodium is in Group 1 and loses 1 electron.
What is the charge on a chloride ion and why?
Cl⁻ — chlorine is in Group 7 and gains 1 electron.
What is the charge on a calcium ion and why?
Ca²⁺ — calcium is in Group 2 and loses 2 electrons.
What is the charge on an oxide ion and why?
O²⁻ — oxygen is in Group 6 and gains 2 electrons.
How do you work out the formula of an ionic compound from its ions?
Balance the charges so the overall charge is zero (e.g. Mg²⁺ + O²⁻ → MgO; Ca²⁺ + 2Cl⁻ → CaCl₂).
What does a dot-and-cross diagram show for ionic bonding?
The outer-shell electrons of each atom before and after transfer, with circles representing each ion's electron shells.
In a dot-and-cross diagram for NaCl, whose electrons are the dots and whose are the crosses?
Conventionally, one atom's electrons are shown as dots and the other's as crosses — it shows which atom each electron originally came from.
Does the ionic bond act in one direction or all directions?
All directions — it is a force between point charges (not directional like a covalent bond).
Why does electron transfer in ionic bonding make both atoms more stable?
Both ions end up with a full outer shell (noble gas configuration), which is the most stable electronic arrangement.
What is the difference between ionic bonding and covalent bonding in terms of electrons?
Ionic: electrons are transferred from one atom to another. Covalent: electrons are shared between atoms.
Give one example of an ionic compound formed from a Group 2 metal and a Group 7 non-metal.
Magnesium chloride (MgCl₂) — Mg²⁺ and 2Cl⁻ ions.
Why does magnesium form a 2+ ion and not a 1+ ion?
Magnesium is in Group 2 and has 2 outer electrons — it loses both to achieve a noble gas configuration.
What is the electronic configuration of Na⁺?
2,8 — the same as neon.
What is the electronic configuration of Cl⁻?
2,8,8 — the same as argon.
AQA: which groups do you need to be able to draw dot-and-cross diagrams for?
Group 1 and 2 metals with Group 6 and 7 non-metals only.

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Learn Ionic bonding properly — interactive practice, marked questions and flashcards.

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