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

2. 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 [http://www.bbc.co.uk/schools/gcsebitesize/img/gcsechem_10.gif]

3. Early Periodic Table J. A. R. Newlands (1865) organized all the elements by atomic mass. Properties repeated every 8 atoms. (musical octaves!) [http://www.bbc.co.uk/schools/gcsebitesize/img/gcsechem_10.gif]

4. Early Periodic Table Mendeleev (1869) publishes 1 st “Periodic Table” The table is arranged so that elements in columns have similar properties. [http://jchemed.chem.wisc.edu/Journal/Issues/2003/Aug/Images/JCE2003p847fig3.gif]

5. [http://web.fccj.org/~ethall/2045/ch5/pt1871.gif]

6. [http://www.dlt.ncssm.edu/TIGER/diagrams/periodic/MendeleevPrediction.gif] The Mendeleev Song

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

8. 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

9. The Periodic Table Today Groups – Each vertical column of the periodic table, also known as families. [http://www.chem4kids.com/files/art/elem_pertable3.gif]

10. The Periodic Table Today Periods – This is each horizontal row of the periodic table. [http://www.chem4kids.com/files/art/elem_pertable3.gif]

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

12. [http://www.chem.gla.ac.uk/teaching/GenChemWeb/assets/PeriodicTable/PTblMk2/PTblGroups.gif]