Development of the Periodic Table Discovery of most of the elements found in today's periodic table were found in the nineteenth century. It took many Scientists to

Development of the Periodic Table

Discovery of most of the elements found in today's periodic table were found in the nineteenth century. It took many Scientists to assemble a table that recorded all of the elements in terms of atomic mass, and similar trends. However one man seemed to have cracked it, Dimitri Mendeleev. He recorded all the elements known at the time that showed trends, electron number and atomic mass. He managed to predict the properties of other elements that hadn't been discovered and left corresponding gaps for them to be placed. However, it is important to note that Mendeleev did not arrange his table in order of atomic mass. This is what made his table different from the rest. His table was a huge Scientific break through as other Scientists had too many flaws in their versions.

The first Scientist to attempt at recording the elements on a table was Johann Dobereiner. He classified them in order of atomic weight (now better known as atomic mass). He also arranged the elements into triads. He used the average of 1st and the 3rd elements in each triad to calculate the atomic weight of the 2nd element in the triad. An example of one triad was: Ca, Sr, and Ba.

John Newlands in 1863 noticed Dobereiner's table was written in order of ascending atomic weight and every eighth element had similar properties. He called this The Law of Octaves. However, after the first 20 elements, he had to put two elements into the same position for it to make sense. Also some of the atomic weights of the elements had been imprecisely measured. He was set on the right tracks but he wasn't quite there yet. Six years after this attempt, Mendeleev had created his renowned periodic table.

As mentioned earlier Mendeleev had ...