Dmitri Mendeleyev is the inventor of the modern periodic table. He presented his periodic table of the elements based on increasing atomic weight on March 6, 1869, at the Russian Chemical Society.
Though he is often cited as the inventor of the modern periodic table, did you know that his table wasn't the first attempt to organize the elements according to periodic properties? In 1864, Lothar Meyer published a periodic table that described the placement of 28 elements.
The periodic table reflects its creator's love for card games. Dmitri Mendeleyev was very fond of card games. That's why he wrote the weight of each element on a separate index card and sorted them as they would be organized in solitaire.
Elements with similar properties then formed a "suit" and were placed in columns that were ordered by ascending atomic weight.
The periodic table was used to correctly predict elements that hadn't been discovered. When Mendeleyev put his original periodic table together there were several blank spaces in it. By estimating their properties relative to other elements near the spaces on the table, Mendeleyev was able to correctly predict the discovery of a few elements.
Today, there are 118 confirmed elements in the periodic table. 90 of those elements are commonly found in nature, others are largely synthetically made.
Technetium was the first element to be synthesized. It was first produced in 1937. Today there are 24 other elements that are primarily produced synthetically.
Four of the elements in the table were only recently named. On 28 November 2016, the International Union of Pure and Applied Chemistry approved the name and symbols for four elements that were previously dubbed elements 113, 115, 117, and 118.
The elements were named nihonium (Nh), moscovium (Mc), tennessine (Ts), and oganesson (Og).