Here's how Mendeleev arranged the elements:
* Atomic Weight: Mendeleev arranged the elements in order of increasing atomic weight. This was a common practice at the time as the concept of atomic number was not yet understood.
* Chemical Properties: He noticed that elements with similar chemical properties appeared at regular intervals in the table. He grouped these elements together into columns, forming the basis of the modern periodic table's groups (columns).
* Predictive Power: Mendeleev left gaps in his table for elements that he predicted would be discovered later. He even predicted the properties of these undiscovered elements based on their position in the table. His predictions were later confirmed with the discovery of elements like gallium and germanium.
Mendeleev's Periodic Table was a revolutionary breakthrough in the understanding of chemical elements. It provided a framework for organizing the vast amount of chemical knowledge that was accumulating at the time and led to the development of modern atomic theory.
