Author: Katie Rosser-Evans

# Covalent bonding

Below is a step-by-step guide of how to use this fun model to help pupils to visualise and understand covalent bonding in a fun and abstract way. You only need the students and some coloured balls (ball pit balls work perfectly) to complete this:

- Select 4 pupils to participate – they will represent an atom.
- Get the pupils to stand in a circle with their backs facing inwards.
- Select an atom (e.g chlorine) and to engage all pupils, ask them which group your chosen element is in and how many outer electrons will it have.
- Give pupils coloured balls (all the same colour). These represent the electrons. The students representing the atom should be given, the same number of electrons as the atom has in its outer shell (with no pupil holding more than 2 balls/electrons).
- Now select a further 4 pupils to participate – they will represent the second atom. They follow the same steps as above (1-4) however with a different colour ball to represent their electrons (i.e if the first atom has red balls, the second could have green).
- Students should now see that neither atom has a complete/full outer shell. This gives opportunity for pupils to suggest how they can fill both shells by only using those two atoms.
- Pupils requiring extra electrons can now share at this point – forming a covalent bond.

This should be repeated a second time with another set of pupils if possible in order for all pupils to see what is happening.

As an extra support feature, if access to giant chalk, the shells can be drawn on the floor to help support the visualization when double and triple bonds are formed.

# Ionic bonding

Below is a step-by-step guide of how to use this fun model to help pupils to visualise and understand covalent bonding in a fun and abstract way. You only need the students and some coloured balls (ball pit balls work perfectly) to complete this:

- Select 4 pupils to participate – they will represent an atom.
- Get the pupils to stand in a circle with their backs facing inwards.
- Select an atom (e.g oxygen) and to engage all pupils, ask them which group your chosen element is in and how many outer electrons will it have.
- Give pupils coloured balls (all the same colour). These represent the electrons. The students representing the atom should be given, the same number of electrons as the atom has in its outer shell (with no pupil holding more than 2 balls/electrons).
- Now select a further 4 pupils to participate – they will represent a second atom (e.g Magnesium). They follow the same steps as above (1-4) however with a different colour ball to represent their electrons (i.e if the first atom has red balls, the second could have green).
- Students should now see that neither atom has a complete/full outer shell. This gives opportunity for pupils to suggest how they can fill both shells by only using those two atoms.
- Pupils representing the magnesium atom can now give their electrons to the oxygen atom – forming their ions. The different colour ball helps show that the electrons are from that of another atom.

To help understanding/visualisation further, shells can be drawn on the floor using giant chalk or represented using different sized hula hoops in order for pupils to help see the that only the outer shell electrons are involved, and to help with the formation of the cation.