Ionic Bonding
Practise Ionic Bonding for GCSE Chemistry with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. Ionic bonding is the transfer of electrons from a metal to a non-metal — practise dot-and-cross diagrams for compounds like NaCl and MgO.
Free downloads
These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Ionic bonding occurs when a metal reacts with a non-metal. Electrons in the outer shell of the metal atom are transferred to the non-metal atom.
Both atoms achieve the electronic structure of a noble gas, which is a stable arrangement. The metal loses electrons to become a positive ion, and the non-metal gains electrons to become a negative ion.
The number of electrons transferred depends on the group. Group 1 metals lose one electron to form 1+ ions, group 2 lose two to form 2+ ions. Group 7 non-metals gain one to form 1− ions, and group 6 gain two to form 2− ions.
Revision notes
The transfer of electrons
Electrons in the outer shell of the metal atom are transferred to the non-metal atom.
Both atoms then have the electronic structure of a noble gas, which is stable. Dot and cross diagrams are used to show this transfer.
Charges on the ions
Group 1 metals lose 1 electron to form 1+ ions. Group 2 lose 2 to form 2+ ions.
Group 7 non-metals gain 1 electron to form 1− ions. Group 6 gain 2 to form 2− ions. The group number tells you directly what charge to expect.
Giant ionic lattices
Ionic compounds form giant lattices in which the ions are held together by strong electrostatic forces of attraction.
These forces act in all directions, which is why ionic compounds have high melting points.
Key points
- Electrons are transferred from metal to non-metal.
- Both atoms achieve a noble gas electronic structure.
- Metals form positive ions by losing electrons.
- Non-metals form negative ions by gaining electrons.
- Group 1 forms 1+ ions and group 2 forms 2+ ions.
- Ionic compounds form giant lattices.
Worked examples
Example 1
Explain what happens to the electrons when sodium reacts with chlorine. [3 marks]
Model answer
Sodium has one electron in its outer shell, which is transferred to the chlorine atom (1 mark). Sodium becomes a 1+ ion and chlorine becomes a 1− ion (1 mark). Both now have the stable electronic structure of a noble gas (1 mark).
Example 2
State the charge on the ion formed by an element in group 2. [1 mark]
Model answer
2+ (1 mark).
Example 3
Explain why ionic compounds have high melting points. [2 marks]
Model answer
They have giant lattice structures held together by strong electrostatic forces of attraction between oppositely charged ions (1 mark), and a large amount of energy is needed to overcome these forces (1 mark).
Common mistakes
Saying electrons are shared in ionic bonding.
They are transferred completely from metal to non-metal.
Getting the sign of the charge wrong.
Losing electrons gives a positive ion; gaining gives a negative one.
Saying the bond is between two ions only.
The lattice has strong forces acting in all directions between many ions.
Forgetting the noble gas structure.
Achieving a full outer shell is why the transfer happens at all.
Exam tips
- Use the group number to work out the ion charge.
- Say transferred, not shared.
- Mention the noble gas electronic structure.
- Explain melting points through strong electrostatic forces in all directions.
Key terms
- Ion
- A charged particle formed when an atom loses or gains electrons.
- Electrostatic force
- The force of attraction between oppositely charged ions.
- Giant lattice
- A regular structure of many ions held together throughout.
- Dot and cross diagram
- A diagram showing the transfer or sharing of electrons.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.