Final answer:
Mendeleev's periodic table was special because it accurately arranged elements based on atomic mass, left spaces for undiscovered elements, and could predict their properties, which when confirmed, led to universal acceptance of his table.
Step-by-step explanation:
What made Mendeleev's periodic table particularly special is that it was the first to gain wide acceptance within the scientific community and made it possible to predict the properties of elements that had not yet been discovered. Dmitri Mendeleev, a Russian chemist, published his periodic table in 1869, organizing elements based on atomic mass and their chemical properties. Unlike his contemporaries, Mendeleev left spaces for undiscovered elements, correctly predicting their existence and properties based on the periodic law. For example, he anticipated the discovery of elements with atomic masses of 44, 68, 72, and 100, which correspond to elements we now know as scandium, gallium, germanium, and technetium. After the subsequent discovery and characterization of these elements, which exhibited properties predicted by Mendeleev, his periodic table became universally accepted. Element number 101, named mendelevium, honors his profound contributions to chemistry. Mendeleev's insights went beyond those of other scientists like Julius Lothar Meyer, making him a seminal figure in the establishment of the periodic table.