Formation of Ions & Ionic Bonds
Chemistry: Cambridge International GCSE Supplement, topic 2.4.2
Formation of Ions and Ionic Bonds
Ions are charged atoms (or groups) formed by losing (positive) or gaining (negative) electrons for stability. Opposite charges attract, forming strong ionic bonds that build crystal lattices.
What are ions?
- Ions are atoms or groups of atoms that carry an electric charge.
- Positive ions have more protons than electrons.
- Negative ions have more electrons than protons.
- Ions form to achieve a full outer electron shell, making atoms more stable.
Formation of positive ions (cations)
- Atoms of metals lose electrons to become positive ions.
- Losing electrons reduces the number of negative charges.
- For example, sodium (Na) loses one electron to form Na+.
- This electron loss helps the atom have a full outer shell like noble gases.
Formation of negative ions (anions)
- Atoms of non-metals gain electrons to become negative ions.
- Gaining electrons increases the number of negative charges.
- For example, chlorine (Cl) gains one electron to form Cl-.
- This electron gain helps the atom have a full outer shell like noble gases.
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How ionic bonds form
- Ionic bonds form between positive metal ions and negative non-metal ions.
- Opposite charges attract and hold the ions together.
- This attraction creates a strong ionic bond.
- Ionic compounds form crystal lattices due to these bonds.
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