Structure triangle: a periodic table for compounds?

The periodic table is for elements, but can we make sense of the millions of compounds in our environment? The answer explained in this PowerPoint presentation is to classify them according to their physical properties, the same properties we use when we recycle – 1: metals, 2: ceramics (glass), 3: plastic and organic waste, paper, 4: volatile waste we send up the chimney or down the drain; 5: ionic substances like ash.
We have just five different sorts of compound. We find the same five groups when we look at the ways elements bond. Forget classifying substances into solid, liquid or gas and go, instead, for these five types: metals, ceramics, life polymers (both biodegradable and plastics), volatile and ionic. We tend to teach bonding as if there are three distinct ‘kinds’: covalent, ionic and metallic, whereas these are just extreme cases. They all start with two atoms sharing electrons.
With two non-metallic elements this results in (polarised) covalent bonding, either building up individual molecules (volatile materials) or building up giant structures (rocks , life and polymers)
with two metallic elements you can never fill the outer electron shells so the atoms close pack with ‘free’ electrons (metals and alloys)
with a metal and non-metal the bond is very polarised and you get ionic bonding (salts etc.)
Before using/adapting this resource for teacher education or for use in school - I strongly recommend reading my article Mapping compound structure and bonding available in Education in Chemistry:
https://edu.rsc.org/ideas/mapping-compound-structure-and-bonding/3007749.article
The “Structure Triangle” is also explained in two short Fuse-School videos:
https://www.youtube.com/watch?v=kNFLsrSpAtA How Do Atoms Bond part 1| Properties of Matter | Chemistry | FuseSchool (Unfortunately the animation shows the PT twisting anticlockwize and it should twist clockwise so Cs is on the left and F is on the right)
https://www.youtube.com/watch?v=cUKifjMhXRo (this is part two – unfortunately the triangles are not drawn equilateral as in part one)
The original idea is fully developed in the Science-Issues resource as a free download www.scienceissues.org.uk After downloading, go to ‘Issues’ then choose ‘Matter’ and work through part 1 “The five types of material” [this has a strong link with the way we sort materials for re-cycling] and part 4 “The structure triangle” [this has an extension for A level/bac examining electron pair bonding]
Keith Ross keithaross@gmail.com