How many elements were in the first periodic table?
Look in this site. You'll find out the answer to this question. http://en.wikipedia.org/wiki/History_of_the_periodic_table
At the time the periodic table was first devised, there were many elements that had not yet been discovered. Their existence could be inferred, but they couldn't actually be put into the table until they were discovered. When the periodic table was first devised, there were lots of elements that had not been discovered yet.