When was the first periodic table published?

The first periodic table was published in 1869 by Dmitri Mendeleev. This table was significant because it organized the known chemical elements based on their atomic mass, which revealed patterns in their properties. Mendeleev's work not only provided a systematic way to look at the elements but also allowed for the prediction of elements that had not yet been discovered. This groundbreaking approach laid the foundation for modern chemistry and the current periodic table, which is organized by atomic number rather than atomic mass. The years leading up to 1869 saw various attempts at categorizing elements, but it was Mendeleev’s version that truly established the periodic law and arranged elements in a meaningful way.