The
PERIODIC TABLE
of the chemical elements is an incredibly useful icon of chemistry, arrived at by a series of developments and observations by experimental scientists, crystallizing in the mid-1800s.
Developed by awareness of repetitions in the property similarities of the known elements, it was charted by Dmitri Mendeleyev for his students (see at right), and first published in 1869 with his "periodic law" presenting that the sequence of elements depended on their weights (later changed to atomic number sequence).
The "fearful symmetry" was evolved, as he said, "independently of any conception as to the nature of the elements." Recent knowledge gained of the structure of atoms has gone far towards explaining the shape of the periodic table, and songs of praise have been sung to it's beauty and power.
The table has undergone many changes; addition of elements, more accurate values, modified references, different column labels, and shifts in element positions.
For a recently updated version of the flat periodic table, useful for reference, set up your printer's page output to horizontal (landscape),click here and print it.
A number of problems with relating the periodic table with the periodic law have been resolved by the recognition that relationships between elements are more clearly and accurately shown in three-dimensional representations.
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Original Mendeleyev Table
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