Ionic and Metallic Bonding
Chemistry: Edexcel IGCSE, topic 6.1.9
Giant Structures and Ionic and Metallic Bonding
Compounds with ionic and metallic bonding form giant structures. These structures lead to specific properties of ionic and metallic compounds.
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Ionic Compounds
- Ionic compounds form giant ionic lattice structures.
- These are held together by strong electrostatic forces (called ionic bonds) between oppositely charged ions.
Properties of ionic compounds
- Giant ionic lattice structures have very high melting and boiling points because lots of energy is required to break ionic bonds.
- When solid, the ions in a giant ionic lattice are fixed in place.
- This means that charges cannot flow, so electricity cannot be conducted.
Metallic bonding
- Metals are made of giant structures of regularly arranged atoms.
- The structure is a regular lattice of positive ions (cations) in a ‘sea’ of delocalised electrons.
Delocalised electrons
- Delocalised electrons in compounds with metallic bonding are not bound to an atom and are free to move around within the lattice.
- Delocalisation happens because metal atoms have a small number of electrons in their outer shells.
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Metals as conductors
- Metals are good conductors of electricity because their delocalised electrons can carry a charge through the structure.
- The electrons move from the negative terminal to the positive terminal.
- The same delocalised electrons can also carry heat energy through the structure.
Test yourself on Ionic and Metallic Bonding
What holds together a giant ionic lattice structure?
What is it about metals' bonding that enables them to conduct heat and electricity?
Why are electrons delocalised in giant metallic structures?