How many elements were uncovered during the discovery of Mendeleev’s periodic table?

Dmitri Mendeleev's periodic table, introduced in 1869, originally classified 63 known elements. However, the number of elements during his time was limited compared to modern standards, and many elements that we know today were not yet discovered. Mendeleev's arrangement predicted the existence and properties of several elements that had not yet been discovered, which were later confirmed. Therefore, while 63 elements were recognized in the original table, Mendeleev's predictions played a crucial role in guiding subsequent discoveries. Over time, as more elements were discovered and understood, the periodic table evolved significantly, expanding to include over 100 elements today.