Should space aliens visit earth, I suggest communications begin with a blank periodic table--anyone capable of space travel would surely recognize the unique shape. So what's the origin of this universally recognized shape or did Mendeleev (father of the periodic table) come down a mountain carrying the famous outline carved in rectangular stone?

The quest for a systematic arrangement of the elements started with the discovery of individual elements (see Discovery of Elements).  By 1860 about 60 elements were known and a method was needed for organization.  In fact many scientists made significant contributions that eventually enabled Mendeleev to construct his table. The periodic table did not end with Mendeleev but continued to take shape for the next 75 years.

Aliens Activity Cards A  B
 

Source of this page:  http://mooni.fccj.org/~ethall/period/period.htm