The periodic table arranges the elements based on their atomic number (number of protons in the nucleus), electron configurations, and recurring chemical properties. Hank Green from Crash Course takes us on a tour of this fundamental table and retells the history of the obsessive man mainly credited with developing it.
While other scientists had their own ideas of how to organize elements in a periodic table, Dmitri Mendeelev’s layout was the first widely recognized table. Mendeleev was so obsessive, that he also predicted some properties of then-unknown elements. Most of his predictions were proved correct. Elements are presented in order of increasing atomic number. On the far left of the table are the extremely reactive alkali metals. On the far right of the table are the totally unreactive noble gases.