OCR GCSE Chemistry Structure
This page covers the following topics:
Ionic compounds form giant crystalline ionic lattices, held together by the strong electrostatic forces of attraction between the oppositely charged ions. The stronger this attraction, the higher the melting point of the ionic compound. If the ions in the lattice are free to move then the compound can conduct electricity.
Small molecules are held together by strong covalent bonds, but weak intermolecular interactions so they're usually gases or liquids at room temperature.
Some elements form giant covalent lattices which are large structures with multiple atoms joined together by covalent bonds. These lattices have exceptionally high melting and boiling points. The layout of the atoms in these structures also determines the physical properties of the compound, ie. hardness, density.
Metals form large structures held together by metallic bonding. Pure metals are usually very soft and malleable, so different metallic elements are mixed to form alloys with preferable properties.
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