Main group elements

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The First 36 Main Group Elements: Hydrogen to Barium


Initially we shall limit our initial discussions to s and p-block elements, to first 36 main group elements, hydrogen to barium:


However, as simple substances in their standard state (1atm pressure and 25°C) the main group elements present as a diverse and complicated collection of substances:


As discussed elsewhere in this web book – see the pages on the Classification of Matter and the Tetrahedron of Structure, Bonding & Material Type pages – elemental and binary substances exhibit four extreme material types [metallic, ionic, molecular & network], however the elements present as just: metallic, molecular & network:



When this analysis is applied to the set of the first 36 main group elements we find:

16 elements are molecular, 15 are metallic, 5 is network covalent (carbon) and none are ionic.
However, this is a gross simplification because several elements have metallic and non-metallic allotropes that are intermediate between metallic and network, and are metalloid or semi-metallic in nature: C, Si, Ge, As, Sn, Sb & Te.

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