How many elements are in the periodic table? Has this number changed over the years?

The periodic table is a table of all the elements known
arranged according to their outer electronic
configuration.

The number of elements in the periodic has
increased over the years that it was created. In 1789 a list of 33 elements was
published by Antoine Lavoisier. Soon scientists saw that based on the chemical
properties of the elements, they could be grouped together with each having similar
properties. By 1864, 49 elements were part of the table.

As
the elements were arranged in the form of lists several gaps were left, these were soon
filled in with scientists discovered more elements over the years. Francium was the last
naturally occurring element to be discovered and this happened in
1939.

Later many new elements created by nuclear
bombardment were introduced into the table. The latest element to be discovered in July
2009 has made the number of elements in the periodic table equal
117.