On 6 March 1869, Russian chemist Dmitri Mendeleev presented his pioneering periodic table of elements to the Russian Chemical Society, revolutionising the understanding of chemical properties and atomic relationships.
By arranging elements according to their atomic masses and recognising recurring patterns in their behaviour, he not only systematised known elements but also predicted the existence of undiscovered ones with remarkable accuracy.
His work laid the foundation for modern chemistry, demonstrating the deep-seated order in the natural world and enabling future scientific breakthroughs.