How Does Mendeleev's Periodic Table Differ From the Present One?

Dmitri Mendeleev's periodic table featured elements arranged in accordance with their atomic mass, while the modern table has elements arranged according to periodic number. Mendeleev's periodic table also had the elements arranged vertically, whereas the modern table has them arranged horizontally.

Another important difference is that Mendeleev's table only had 63 elements. The modern table consists of 118 elements. However, there are similarities between the two tables. In both tables, elements are arranged by groups and families. They are also arranged based on the similarities in their chemical properties.

Mendeleev is considered the father of the periodic table. Even though his original table came with fewer elements, he was able to predict the discovery of several elements and provided spaces within the periodic table for these elements. This includes the elements Gallium, Scandium, and Germanium. He also predicted the properties and work out the atomic mass of these elements, long before they were discovered.

Born in 1834, Mendeleev was a Russian chemist and inventor. He reportedly noticed the similarities between the chemical properties of different elements while working on his textbook, "Principles of Chemistry." His discovery led him to publish what would become known as the Periodic table. Although Mendeleev was nominated for a Noble Prize in Chemistry, he never won one. The element Mendelevium (number 101) is named in honor of him.