Learn about chemical bonding.
This lesson includes:
- two videos explaining ionic and covalent bonding
- two activities
All compounds are held together by chemical bonds. A bond is formed as a result of the interaction between two atoms or ions.
There are three primary types of bond:
- ionic bonds
- covalent bonds
- metallic bonds
Watch this video where Fran Scott explains the principles around ionic bonding.
Watch this video where Fran Scott this time explains the principles behind covalent bonding.
Metal bonds are very similar to ionic bonds, in that the atoms use opposite charges to bond together. However in metals, electrons are not fixed in place around the nucleus. Instead they are delocalised throughout the whole structure, resulting in very strong metallic bonding.
The delocalised electrons also contribute to two major properties of metals:
- they are good conductors of electricity
- they are good conductors of heat
This is because the electrons allow electric charge and heat energy to pass freely throughout the whole of the metal.
There are lots of ways to try out your science skills.
Another major property of metals is that they can be bent and hammered into shape ie. they are malleable.
Using your knowledge of metallic bonding, can you think why this might be?
Once you've had a think, you can check the answer at the bottom of this guide.
Try this quiz and say whether each compound is ionic or covalent.
Activity 1 - ANSWER
When metals are hit by an external force, the energy created is transferred throughout the metal by the delocalised electrons.
Metallic bonds are extremely strong, so this delocalised energy is not enough to break these bonds.
What happens instead, is that the rows of atoms slip and slide over one another, maintaining their bonds to one another.
There's more to learn
Have a look at these other resources around the BBC and the web.