Ionic bonding and structure

Ionic Bonding

Ionic bonding is the attractive force between ions of opposite charge. It involves the transfer of electrons from a metal atom to a non-metal atom to form ions.
Each ion becomes electrically charged: The metal becomes a positively charged cation and the non-metal becomes a negatively charged anion.
This transfer of electrons allows both the metal and non-metal atoms to achieve a full outer shell of electrons, reaching a more stable electronic configuration.
Examples of ionic compounds include sodium chloride (NaCl), potassium bromide (KBr), and calcium oxide (CaO).

Structure of Ionic Compounds

In ionic compounds, the ions arrange themselves in a regular three-dimensional structure called an ionic lattice.
In this ionic lattice, each ion is surrounded by ions of the opposite charge. This maximises the attractions and minimises the repulsions between the ions, creating a stable structure.
The crystal lattice structure is hard, with a high melting and boiling point due to the strong electrostatic forces between the positive and negative ions.
Because of these forces, ionic compounds usually occur in a crystalline solid form at room temperature.
Ionic compounds are also able to conduct electricity when dissolved in water or melted, as the ions are free to move and carry current.

Properties of Ionic Compounds

Ionic compounds have high melting and boiling points due to the strong electrostatic forces between their cations and anions which require a significant amount of energy to overcome.
As mentioned above, they conduct electricity when dissolved in water or melted, as this allows their ions to move and carry a current.
In solid form, however, ionic compounds do not conduct electricity as the ions are not free to move.
They are also brittle – when an external force is applied, the ions can shift and like charges can align, causing repulsion and making the crystal shatter.

Please ensure you become familiar with the key concepts presented here. They form a foundational understanding for the study of ionic bond formation, ionic compound structure, and their properties. Practice drawing the ionic bonding of different pairs of atoms, as well as recognising and explaining the physical properties of ionic compounds.