The atomic weight, relative atomic mass, is roughly proportional to atomic number because valency, which manifests itself in the chemical composition, is based on the outermost electrons of an atom; Mendeleev had chosen the two properties that in his day most nearly reflected the fundamental principles on which the table today is based.
Mendeleev completed his version of the table in 1869, when 63 known elements existed. As Mendeleev said, “If all the elements can be arranged in order of their atomic weights a periodic repetition of properties is obtained. Mendeleev arranged the elements according to weight, and then proceeded to group them into clusters of elements that possessed similar properties. These groupings, together with the consideration of variance from strict atomic weight order, left spaces in the table that Mendeleev predicted would encompass elements that had not yet been discovered. Mendeleev left these spaces open in order to accommodate future discoveries. He himself accurately predicted three of these missing elements- Scandium (ekaboron), Galluim (Ekaalumium), and Germanium (ekasilion).
Mendeleev’s and Meyer’s tables were similar- they acknowledged each other’s work - the differences are subtle but important.
Meyer’s table was an accurate accounting of the known facts about each element, such as the melting point and atomic volume. The table clearly showed the existence of periodic chemical families. In 1870 Meyer’s table and description of the periodic law was published in Liebig’s Annalen.
However a year earlier, the 35-year-old Mendeleev presented a much bolder and scientifically useful table. The Russian Chemical Society enthusiastically received his paper, “On the Relation of the Properties to the Atomic weights of the elements”. In it, the periodic relationship between chemical groups, that is, elements with a similar stoichiometry of reaction, is clearly illustrated. In a scientific triumph, gaps in the table accurately predicted undiscovered elements.
Although Mendeleev’s table is nearly 130 years old, it differs a little from the charts on the walls of laboratories today. The insight obtained in that productive decade resulted in a tool that furthers understanding and eases the use of chemistry in every laboratory in the world.
This periodic table above is a smaller version of the periodic table, which you may see in every laboratory that you go in to. It is the one has been changed again and again because so many people have worked hard on making it, just to make it easier for other people to use and understand.
Below is a table that gives the facts about the history of the periodic table. It tells you who contributed to what part of the table and the year at what it was contributed.
The first ever elements that was found was earth, air, fire and rain by Aristotle according to this table. The latest edition of the elements to the table according to this table is the Synthesised transuranic elements by Glenn Seaborg in 1940.
This table was taken from .
In conclusion there were ten really educated and determined people who put the final periodic table together, they were Aristotle, Antoine Lavoisier, Jöns Jakob Berzelius, Johann Döbereiner, John Newlands, Lothar Meyer, Dmitri Mendeleev, William Ramsay, Henry Moseley, and Glenn Seaborg. These were the main people that children and chemists recognise today as the makers of the periodic table and thank them for it as it has made it a lot easier for to know what to do with certain elements and the dangers when working with then. The main person that people today recognise with the periodic table is Dmitri Mendeleev as his part was one of the most important parts as he showed that you could predict the next element that you leave a space for, and the arrangement of the periodic table.