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Period: to
Development of the Periodic Table
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Discovery of the first element
The first element was discovered by Henning Brand in 1649. He was a German Chemist who through his discovery of phosphorus, became the first known discoverer of an element. He did this by conducting an experiment with his urine, after a few processes, he was able to discover phosphorus. -
1st Periodic Table Development
A French Professor, Alexandre Béguyer de Chancourtois made a significant advancement towards the periodic table in 1862. His contribution was the ‘vis tellurique’ translating to telluric screw which is a 3D arrangement of the elements. This screw plotted the atomic weights of the elements on the outside of the cylinder, so that one revolution equalled an atomic weight increase of 16. This method showed some trends. He was the first to use a periodic table arrangement of all the known elements. -
2nd Contribution to the Periodic Table
In 1864 an English chemist, John Newlands discovered that if the elements were arranged in order of atomic weight, there was a similarity every 7 elements. He called this the ‘law of octaves’, referring to the concept similar with music. The noble gases were not discovered yet, therefore there were only 7 not 8 in his table. There were 62 discovered elements. He did not leave any gaps for undiscovered elements, so he had to cram two into one box, leading to some error in the publication. -
3rd Contribution to the Periodic Table
Lothar Meyer’s first table contained 28 elements, organised by their valency. This table included the main group elements, and his later table in 1868, incorporated the transition metals in more of a developed table. This time, listing the elements in order of atomic weight and elements with the same valency arranged in vertical lines. His work was not published until 1870. He also made notes on molar volume. -
4th Contribution to the Periodic Table
Russian chemist Dmitri Mendeleev, produced a periodic table based on atomic weights but arranged them ‘periodically’ in 1869. He found similarities in elements and patterns of properties recurring. He had similar elements arranged in vertical lines as we see today. He switched some around from the original order to fit certain properties. He left gaps for undiscovered elements. His contribution was so successful that it is the basis of the modern periodic table. Element 101 was named after him. -
5th Contribution to the Periodic Table
William Ramsay was a Scottish chemist who in 1894, discovered the noble gases. He realised that these elements did not have the properties of all the other elements, so he developed a new group in the periodic table called the noble gases. The noble gases are neon, argon, krypton etc. These gases were also known as inert gases as scientists thought that they could not react with any other elements, therefore gaining them an area on the periodic table. -
6th Contribution to the Periodic Table
The periodic table was arranged by the atomic mass with a few exceptions, but it was finally determined why by Henry Moseley in 1914. He fired the new X-ray gun at samples of the elements and measured the wavelength. This was an accurate way of getting the atomic number, giving the exact order of the periodic table. The amount of energy emitted depends on the attraction of the electrons towards the nucleus. The more protons, the stronger the attraction, the more energy emitted. -
7th Contribution to the Periodic Table
In 1940, American chemist, Glenn Seaborg artificially produced heavy mass elements. He was the co-discoverer of the ten elements including plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium and element 106. These elements were then part of a new block in the periodic table named ‘actinides.’
