Lifelong Learning Programme

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Title of the Experience
Molecular geometry
Name of the teacher
Elena Margheri
Country where it took place
School typology
Vocational School
Thematic Area
Experience typology
Teaching in class, Online Learning
Type of contact
Description of the Experience
A good comprehension of molecular geometry is very important to understand the chemical reactivity and the physical properties of substances and it is mandatory for a fruitful approach to organic chemistry in higher technical classes.
Through VSEPR theory, students learn that the arrangement around a central atom is due to the number of electron pairs, repulsing each other because of their negative charge. This repulsion determines the actual molecular geometry.
Approaching this issue, in my experience, students often find 3 kinds of difficulties:
1. they do not realize that the molecules drawn on their textbook or on a blackboard have a three-dimensional structure;
2. they forget that not only bond electron pairs, but all the electron pairs around the central atom, repulse each other and stay at the maximum distance;
3. among the different geometries, the tetrahedral one is the hardest to be understood. We built, in classroom, a paper tetrahedron and we used the “stick and balls” models; however, they found it difficult to locate the central atom and the correct bond angles.
The use of molecular drawing programs was useful; in fact, they make the visualization in the space of molecules easy, showing their three-dimensional structure under different perspectives. I found also some useful web sites that allow students themselves to build different molecules, not only simple ones, and to observe peripheral atoms bound to the central one as well as non-bonding-electron pairs, in their orbitals.
The use of these programs catches the interest of the students, because they can build molecules, foreseeing and then confirming molecular geometry, and, above all, they can play with their colleagues, competing in finding the right geometry.
In my opinion, ludic activity is an important instrument to attain both comprehension of an argument and, above all, a good disposition of mind towards the study of a subject. Competing with colleagues, joking and defusing mistakes can contribute to build “empathy” among students and it is another way to bring out mind speed, aptitude and team working skills. It is a teacher’s work to develop these abilities in young students, looking for different activities besides the lab one.

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Dissemination Seminar in Florence

31 October 2015 The seminar has been held in ITIS “A. Meucci” one of the schools involved within Goerudio project activities. Its main aim was to promote the results of the project toward a broad sample of stakeholders even overcrossing the number of people directly involved in the production of project outcomes. This purpose has been totally achieved especially thanks to the participation of students and teachers coming from different schools or from other classes instead of those ones directly involved within the project activities.