What is the value of the periodic table?

There are many ways in which the periodic table is a valuable tool of science. It is a tabular arrangement of the known elements, with an order based on atomic number (i.e. number of protons) and a layout based on other properties including electron configuration and chemical properties.

By ordering the elements in this way, the periodic table allows generalisations (or predictions) to be made about elements simply by their proximity to other elements in the table; it shows elements with similar constitutions have similar chemical properties. It also serves as a concise way to categorize the elements together in one place, outlining known elements and those that may yet to be discovered. For example, the current period table groups elements from atomic number 1 (hydrogen) to atomic number 118 (organesson). Many of the elements at these extreme atomic numbers are unstable yet they still exist, and many more elements likely exist that we have yet to discover. The periodic table allows the reader to rapidly visualise the suite of known elements in a meaningful way, whilst exposing the limits of our current knowledge.