Early Periodic Table 1700’s about 30 elements listed. Mostly metals used for constructive purposes, with a few non-metals.

Early Periodic Table J. W. Dobereiner (Early 1800’s) formed groups of 3 called “triads”. Properties of the “middle” element are roughly the average of the other two [

Early Periodic Table J. A. R. Newlands (1865) organized all the elements by atomic mass. Properties repeated every 8 atoms. (musical octaves!) [

Early Periodic Table Mendeleev (1869) publishes 1 st “Periodic Table” The table is arranged so that elements in columns have similar properties. [

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[ The Mendeleev Song

Early Periodic Table Moseley (early 1900’s) develops the Periodic Law that arranges elements by atomic number.

Early Periodic Table Periodic Law – When elements are arranged in increasing atomic number, their physical and chemical properties show a periodic pattern. Click Here for The Dynamic Periodic Table

The Periodic Table Today Groups – Each vertical column of the periodic table, also known as families. [

The Periodic Table Today Periods – This is each horizontal row of the periodic table. [

Metals – left of “zig-zag” Nonmetals – right of “zig-zag” The Periodic Table Today

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