Learning should be fun, and where better to start than with science.
If you mention science lessons to anyone over thirty years old, then they’ll remember bunsen burners, white coats and explosions: nowadays the experimental ‘hands-on’ style of teaching seems long forgotten, owing to health and safety concerns, as well as curriculum changes. It doesn’t have to be like this.
The Periodic Table of Elements can be taught and remembered forever by introducing experiments and a few simple ‘period’ and ‘group’ rules.
I always set each student in the class a homework before the topic starts – they each have an element to research. I ask them to produce an A4 sized poster for me, which needs to include a photo of something produced from the element, a description of properties, and a classification (metal, non-metal) and a phase at room temperature (solid, liquid or gas). These are then assembled in their correct order as a wall-decoration, in the Periodic Table of Elements format.
Within minutes, the students can see between the first twenty-eight and thirty-two elements (the number of students in a class), and make assumptions about the reasons why they are placed in a particular category. They can determine reactivity, whether the element is a metal or a non-metal, and spot trends down a group.
The next step is to produce the concept of chemical symbols (which they have seen from homework) and why the atomic number of each element increases across a period.
Protons, electrons and neutrons are the next point in a discussion – associating an electron with each proton to balance the charge, with neutrons adding to the mass number. By relating this to ‘their own’ elements, we then ‘place’ an unknown element in the correct place on the Periodic Table, based on how many full outer electron shells (the valency shell) the electrons occupy.
A full valency shell will contain eight outer electrons, which tally with the group numbers or the table. The argument goes a little like this: If an element has three outer electrons is it easier to lose three electrons to get to the nearest outer shell or gain five to make a full shell of eight…within seconds, the students grasp the concept, and can place the element in group three.
This is an easy method, which involves student interaction in the planning stage. The next step is to ‘show’ them the materials, predict which will react together, and ‘do’ a series of simple (but safe) experiments that can show the theory in practice.