Letters to the editor

●   I have found the recent opinion pieces by Michael Jansen to be very thought provoking, particularly “Chemistry: It’s not fun” (page 3, October issue) and the letters in response (pages 8 - 9, December/January issue). If fun here is taken to mean a very undemanding curriculum without sufficient rigor to support understanding and further study of chemistry, then no doubt the readers of Chem 13 News will be unanimous in agreeing with Michael Jansen. On the other hand, if “fun” is taken to include a variety of learning activities, appropriate to the age and level of the students, such as games, puzzles, artwork, model building, experiments, projects, assignments, etc., in the context of an appropriately demanding curriculum, that is another matter.

In the latter context, the article “Holiday molecules” by Jennifer Pitt-Lainsbury (page 3, December/January issue) and the accompanying photograph reminds me of one area where I think I did give my college students some appropriate fun — a VSEPR and model building assignment. The VSEPR part of the assignment was described in my article “A pseudo-individualized assignment for VSEPR theory” (pages 4 - 6, December 2000 issue). What was not described in that article was Part 2 of the assignment, the model building exercise. It will surely be difficult for a learner to comprehend large areas of organic and inorganic chemistry, the solid state, catalysis, biochemistry, etc., without a solid (pun intended) understanding of the three-dimensional shapes involved.

In my assignment, by means of a mail merge, each student was confidentially assigned five given formulas, one each from these lists:

  • Linear family: N3-, NO2+, CN22-
  • Planar triangular family: BF3, BCl3, BBr3, NO2-, O3
  • Tetrahedral family: ClO3-, NF3, NCl3, NBr3, SO32-, PO33-, ClO2-, OF2, IF2+, BrF2+, S32-
  • Trigonal bipyramidal family: I3-, IF2-, BrF2-, IF3, BrF3, IF4+, BrF4+, SF4
  • Octahedral family: IF5, BrF5, SbF52-, AsF52-, XeF4, IF4-, BrF4-

Their first task was to report the VSEPR geometry of each formula, without explanation, so the marking was very easy and rapid. After giving them in return, privately by mail merge, a mark and the correct answers, their second task was to build a small, ‘shoe-box’ model set of all five structures, including the lone pairs of electrons.  The shoe-box format allowed me to transport the models easily for marking purposes. This kind of task may not be appropriate for secondary school or university students, but in general college students love to combine the abstract and the hands-on. Over a decade or so, and after roughly 400 model sets, I’ve found the amount of handicraft ability and creativity unleashed by this assignment was amazing. Marking the submitted models was a great pleasure, and each year some of the best model sets were displayed for a time in a prominent place in our department. The formulas used in the assignment, except for the first six on the lists, were chosen to each have at least one lone pair of electrons. They are all taken from the pages of “Chemistry of the Elements”,1 have all been synthesized and characterized, and are known to have the shape predicted by VSEPR theory, allowing for distortions due to lone pairs.

The December 2000 article will be posted online under “Supplemental materials” on the Chem 13 News website. If you are interested, student instructions, models marking rubric, form letters, and table-format data files are available from me by email. You can edit and customize the Microsoft Word files to your requirements.

In her article, Jennifer Pitt-Lainsbury gives some further information about Ron Gillespie of McMaster University, co-creator of VSEPR theory. The other co-creator was Sir Ronald Nyholm, FRS (1917-1971)2,3,4. He was an Australian. He taught in a secondary school for a year (a condition of his university scholarship) worked in industry, lectured at a technical college, saw WW2 service as a Gas Officer, and did a PhD at University College London (UCL) under Sir Christopher Ingold. In 1955 he came back to UCL as a professor. He was a transition metal chemist. He headed the chemistry department of UCL from 1963 until his death in 1971. He was very active in the promotion of chemistry and science, and in education and the creation of new curricula. He was knighted in 1967 for “services to science”. (A disclaimer: I was at UCL from 1963 to 1966 doing a BSc in chemistry.)


  1. N. N. Greenwood and A. Earnshaw, Chemistry of the Elements, 2nd Edition, Butterworth-Heinemann, Oxford, 1997 (ISBN: 0 7506 3365 4).
  2. Wikipedia: https://en.wikipedia.org/wiki/Ronald_Sydney_Nyholm.
  3. Royal Society of Chemistry: http://www.rsc.org/ScienceAndTechnology/Awards/NyholmPrizeEducation/.
  4. Chemistry Department, University College London: http://www.chem.ucl.ac.uk/resources/history/people/nyholm.html.

David Cash
Mohawk College (Retired)

●   Regarding “Stop telling us how to do our job” by Michael Jansen, December 2013/January 2014, Chem 13 News page 5:

Does Mr. Jansen not understand that mere chemistry teachers cannot be trusted to know what is beneficial for the students? Surely elected officials and their advisors — who may have no chemistry background whatsoever — know exactly what our students need or do not need. Our administrators — many trained in English, History, Special Education and Physical Education — must understand the needs of the chemistry classroom beyond a mere mortal like Mr. Jansen. Basically when it comes to teaching, leave it to the education experts since all the subjects are the same, aren’t they?

It should be the job of the administrators to worry of an injury resulting from a student spilling 0.0100 mol/L acetic acid, or even worse a spill of solid halite, sucrose or sodium hydrogen carbonate. Students might even have to use dangerous chemicals such as a household dish detergent and dihydrogen monoxide to clean up spills.

As well, we definitely need computers for every student in the chemistry classroom so students can safely watch YouTube experiments — much safer than doing something with actual “chemicals”. It is outdated to embrace the Benjamin Franklin quote: “Tell me and I forget, teach me and I may remember, involve me and I learn.” For a true visual learning experience should be enough to generate a deep understanding of chemistry. Students will then be ready to face future decisions about our safety and environment.

And texts and curricula should not be left to classroom teachers. This allows for foundational background information be left out, leaving students confused. Then students will learn that “chemistry is difficult” — an understanding they will take with them into adulthood. This motivates students to turn to truly important areas such as business, law, psychology and philosophy. The benefit is chemistry jobs are left open for the few still actually willing to attempt to continue with studying chemistry — this is a positive result since we really only need a few chemically-educated individuals in our society.

Really, what do chemistry teachers know about teaching their subject?

Andy Cherkas
Stouffville ON [Andy is known for his weird sense of humour and sarcasm, and has just retired after 40 years in the classroom.]