Developing a modern periodic table: from spirals to the stars
The periodic table is one of the most iconic images in science, a guide to the chemistry of our world. But it's only one among many visual ways to classify the elements.
The earliest attempts to classify elements
The earliest attempts to classify matter were based on the idea of essential qualities, or elements. Grouping chemical substances together according to similar qualities had practical value for alchemists and apothecaries, but there was no consensus or underlying order.
Antoine Lavoisier
In 1789 one leading moderniser, the famed French chemist Antoine Lavoisier, produced a list of 33 ‘simple substances’ that made up the 300 or so chemicals known at the time, categorised by gases, metals, non-metals and earths.
John Dalton
John Dalton, a Manchester schoolteacher, introduced the idea of classifying elements by the relative weight of their atoms in 1806 — a revolutionary concept at the time, which would be crucial to the invention of periodic tables.
Today we know of 118 elements that can be combined to form over 70 million different chemical compounds, so having a system to classify these at an elemental level is crucial.
What is a periodic table?
'Periodic' tables are named as such because they order elements in such a way that their chemical properties repeat periodically after regular intervals. The Russian chemist Dmitri Mendeleev devised his first table in 1869.
Mendeleev's periodic table looked unlike the modern form we know today, as the elements were arranged by ascending weight downwards, rather than across. But Mendeleev’s periodic table was not the first.
What did the first periodic table look like?
In 1862 the French geologist Alexandre-Émile Béguyer de Chancourtois published a paper describing a classification of the elements. De Chancourtois' 'telluric screw', as he called it, placed the elements in order of atomic weight in a spiral pattern around a cylinder.
Like Mendeleev’s table, de Chancourtois had stumbled upon a periodic repetition of chemical properties in his arrangement. Unluckily for him, the ground breaking paper escaped the attention of chemists for decades, largely because the publisher did not include a diagram.
See how de Chancourtois' system worked in practice
Alternative periodic systems
Perhaps the most important periodic system post-Mendeleev was a three-dimensional double spiral system by English scientist William Crookes in 1888. Crookes' original model physically embodies one of the first evolutionary theories of the elements.
Crookes’ periodic system illustrated his theory of the evolution of the elements. In this, elements formed in a plasma inside stars. As temperatures cooled, they evolved from the lightest element, hydrogen, at the top of his spiral, to the heaviest, uranium, at the bottom.
Periodic table (2019) by Jason K. K. Chan Science Museum
Around 700 alternative periodic tables emerged after Mendeleev’s 1869 version, taking shapes like spirals, helices, and zig-zags. Despite their differences, they all follow the periodic law: elements form repeating groups when arranged by increasing atomic number.
Is the famous periodic table the final one?
Even the famous version provokes fierce debate among chemists about where certain groups or elements, like hydrogen, should be placed. And as new elements are added, it will continue to evolve.
The proliferation of periodic tables not only reflects the ongoing scientific endeavour to classify the world around us. It also shows, as these tables have made the journey from textbook to tea mug design, how rooted science is in our cultural life.
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