## Wednesday, 12 June 2013

### Helical Periodic Table

Flying in the face of nomenclature, the classic Periodic Table doesn't quite fit into a two-dimensional, rectilinear grid. There have been many attempts to improve the layout, some of which turn to the third dimension to solve the problem of those pesky lantha­nides and acti­nides. One of the most pleasing is Mendeleev's Flower, but even this is quite complicated and fiddly.

I decided to design a simple, three-dimensional, paper construction myself, based on data from Wikipedia. Here's a Google SketchUp rendering of my first attempt:

Each cell has six pieces of information:
1. Top-left: the atomic number;
2. Top-right: the atomic mass (or most stable mass number in square brackets);
3. The chemical symbol;
4. The English name;
5. Bottom-left: the element's state at zero Celsius and one atmosphere pressure; and
6. Bottom-right: the date of discovery or first isolation.
Here are the construction sheets for cutting out and gluing. Use the SVGs: they employ vector graphics.

There are little glue tabs to help you create the cylinders. Glue the purple strip within the gap in the lower-left corner of the main table.

So well and good, but the eagle-eyed amongst you may have noticed that with the cylindrical scheme although hydrogen (Z=1) and helium (Z=2) are neighbours, helium (Z=2) and lithium (Z=3) are not.

The solution is to use a helical layout: the atomic numbers then spiral down in sequence. But in order for the construction to sit nicely on a flat surface, we need to skew the cells slightly:

I think it's fairly obvious how to make, but just in case...

First, print out the SVG on the largest sheet you can:

Then, cut out the two sections and fold forward the glue tabs:

Next, glue the lower section within the gap of the main table:

Finally, form a cylinder of the main table:

It's as simple as that. Not exactly nuclear physics...

UPDATE 2016-10-22 : As 'unlikelygrad' kindly pointed out, I misspelled "Noble Gases" in the original PDFs, so I've corrected that and uploaded the files as SVGs (there's now much better native support in browsers)