Periodicity – Topic 3 and 13

This follows on from yesterdays posting – just a couple of ideas for labs work you could carry out when teaching this topic. I should stress that this is only a list of ideas / suggestions and that if you intend using any of these ideas to assess for IA, please ensure that they are given to the students in the appropriate format.

• Discuss similarities and differences between elements in the same group – this lends itself to a lab on the reaction of some group 2 metals (calcium, magnesium (possibly) strontium and barium. You could look at how some of them react with water, the solubility of hydroxides and sulfates.
• The other alternative is to look at the displacement reactions of the halogens and the halides.
• Looking at the period 3 oxides and chlorides – you could look at their appearance, reactions with water and resulting pH of the solution and electrical conductivity.
• Transition metals – there are many reactions to look at here but in particular the oxidation states and colours of vanadium. This involves reducing vanadium from +5 to +2. You can read more about this lab here (http://www.chemguide.co.uk/inorganic/transition/vanadium.html).
• You can also use a colorimeter to determine the formula of a complex ion (http://www.calpoly.edu/~cbailey/ComplexIon/ComplexIon.html).
• Finally, a little piece of cross Chemistry work but you could investigate reactions with and without transition metal catalysts (for example, the decomposition of hydrogen peroxide –http://www.york.ac.uk/chemistry/schools/chemrev/projects/peroxide/).

Good luck!

It goes without saying that some of these labs are potentially very hazardous indeed and you are responisble for ensuring that appropriate risk assessments are carried out.