Ask most chemists who discovered the periodic table and you will almost certainly get the answer Dmitri Mendeleev. Certainly Mendeleev was the first to publish a version of the table that we would recognise today, but does he deserve all the credit?

A number of other chemists before Mendeleev were investigating patterns in the properties of the elements that were known at the time. The earliest attempt to classify the elements was in 1789, when Antoine Lavoisier grouped the elements based on their properties into gases, non-metals, metals and earths. Several other attempts were made to group elements together over the coming decades. In 1829, Johann Döbereiner recognised triads of elements with chemically similar properties, such as lithium, sodium and potassium, and showed that the properties of the middle element could be predicted from the properties of the other two.

It was not until a more accurate list of the atomic mass of the elements became available at a conference in Karlsruhe, Germany in 1860 that real progress was made towards the discovery of the modern periodic table.

This area of the website celebrates the work of many famous scientists whose quest to learn more about the world we live in and the atoms that make up the things around us led to the periodic table as we know it today.

Chemists have always looked for ways of arranging the elements to reflect the similarities between their properties. The modern periodic table lists the elements in order of increasing atomic number (the number of protons in the nucleus of an atom). Historically, however, relative atomic masses were used by scientists trying to organise the elements. This was mainly because the idea of atoms being made up of smaller sub-atomic particles (protons, neutrons and electrons) had not been developed. Nevertheless, the basis of the modern periodic table was well