Experiences

Electronegativity and periodic properties- general chemistry

Laura Capella

Italy

Vocational School

Chemistry

Laboratory

Direct

This experience has been performed in a second year High School Course (15 years old students) and is suitable for1st-2nd year.

In my experience I often found it difficult to make students really understand
the importance of knowing well the periodic properties of the elements.
This matter is usually situated in the second part of the first year of
Italian High School (14-year-old pupils). Often students learn mechanically, if they do, the definition of each property just for the text examination but always forget it immediately after. They can’t understand why they have to memorize not all, but, at least, some values just to make them orienteering within the Periodic Table.
The less understood of these properties, in my opinion, is Electronegativity.
This observation made me think I should not explain this property together
with the others with the description of the Periodic Table during the first year: I started to just mention electronegativity (maybe saying just few words
because sometimes there is one or two students that worth this effort),
and, instead, to present it directly in the second year, just prior to
introduce Chemical Bonds.
In fact, it is only at this point that the real importance of it is
revealed to students. Anyway it is a good choice to make sure they
appreciate the necessity of knowing well this subject. For this reason I
find it useful to make the following experience.
First, the reading of a stimulating story, picked from a graceful booklet:
"The periodic Reign" from P. Atkins, to prepare the work. (See the
chapter 3 of the first Part: Physic Geography)
Then, we started with a manual group job. Each group was given a photocopy of the Periodic table and a set of little chips (say, toy bricks or simply Italian "pasta" or little candies) of the same shape and
dimension. Every group (three membered groups) was assigned a
periodical Group, I, II, III group until VIII (noble gases). With the help of
periodic Table they found periodical property values (First Ionization
Potential, ecc. until to Electronegativity) for each Element of their
assigned Group.
Giving to chips a specific value for every different periodical property,
they started to build little columns with chips and glue: one for each
Element. When all the groups had finished to make element–columns for every property we had chosen to analyse, they built the entire Periodic table (except for transition metals and block f) assembling chips–elements, sticking them all to a single Periodic Table put on a wooden tablet.
At the end we had the Electronegativity 3-D model and more 3-D models for
all the periodic properties groups had done (i.e. only First Ionization
Potential, and Electronic Affinity).
After that the visual memory of these work helped them to memorize well and
to understand better Periodical properties.