We have been learning how various things or living beings can be classified based on their properties. Even in other situations, we come across instances of organisation based on some properties. For example, in a shop, soaps are kept together in one place while biscuits are kept together elsewhere. Even among soaps, bathing soaps are stacked separately from washing soaps. Similarly, scientists made several attempts to classify elements according to their properties and obtain an orderly arrangement out of chaos.
The earliest attempt to classify the elements resulted in grouping the then-known elements as metals and non-metals. Later further classifications were tried out as our knowledge of elements and their properties increased.