In 1869, Russian chemist Dmitry Mendeleev published the first draft of the periodic table of elements. His table arranged the elements in order of atomic weight -from lightest to heaviest- and included gaps where Mendeleev made predictions of yet unknown elements. Mendeleev’s table also grouped the elements by likeness, periodically ignoring the order suggested by atomic weight in order to group them more effectively by similarity. In doing so, Mendeleev unintentionally listed the elements in order of atomic mass!
Scientist speculate the first element discovered was copper, as early as 9,000 BCE in the Middle East.
Only 90 elements occur in nature. The others are strictly man-made.
Scientists continue to discover new elements. The most recently confirmed discovery dates back to the year 2,000 when researchers bombarded curium with calcium to discover livermorium.
Wow! I never knew that the periodic table had such history or that there were so many man made elements! Although the last manmade element was discovered 2000 years ago, it will be interesting to see whether a new one is discovered during our lifetime!