Every substance in the universe, from the air we breathe to the stars in the night sky, is composed of fundamental building blocks - The elements. This interactive slideshow quiz challenges you to identify these elemental components, one by one, as you delve into the heart of chemistry. Discover the genius of Dmitri Mendeleev, who in 1869 published the first recognizable Periodic Table, arranging the then-known 63 elements and even predicting the existence of others like Gallium and Germanium. Learn how Henry Moseley later refined this order by atomic number in 1913, solidifying its modern structure. Are you ready to test your knowledge of the elements and unravel the secrets of their organization?